# Mini-XML Programmers Manual, Version 2.2.1

Michael Sweet
Copyright 2003-2005

# Table of Contents

Introduction

- Legal Stuff
- History
- Organization of This Document
- Notation Conventions
- Abbreviations
- Other References

1 - Building, Installing, and Packaging Mini-XML

- Compiling Mini-XML
- Installing Mini-XML
- Creating Mini-XML Packages

2 - Getting Started with Mini-XML

- The Basics
- Nodes
- Loading XML
- Saving XML
  - Finding and Iterating Nodes

3 - More Mini-XML Programming Techniques

- Load Callbacks
- Save Callbacks
- Custom Data Types
- Changing Node Values
- Formatted Text
- Indexing

4 - Using the mxmldoc Utility

- The Basics
- Code Documentation Conventions
  - Functions and Methods
  - Variables and Class/Structure/Union Members
  - Types
  - Classes, Structures, and Unions
  - Enumerations
- XML Schema

A - GNU Library General Public License

- How to Apply These Terms to Your New Libraries

B - Release Notes

- Changes in Mini-XML 2.2.2
- Changes in Mini-XML 2.2.1
- Changes in Mini-XML 2.2
- Changes in Mini-XML 2.1
- Changes in Mini-XML 2.0
- Changes in Mini-XML 1.3
- Changes in Mini-XML 1.2
- Changes in Mini-XML 1.1.2
- Changes in Mini-XML 1.1.1
- Changes in Mini-XML 1.1
- Changes in Mini-XML 1.0
- Changes in Mini-XML 0.93
- Changes in Mini-XML 0.92
- Changes in Mini-XML 0.91
- Changes in Mini-XML 0.9

C - Library Reference

- Contents
- Enumerations
  - mxml_type_e
- Functions
  - mxmlAdd()
  - mxmlDelete()
  - mxmlElementGetAttr()
  - mxmlElementSetAttr()
  - mxmlEntityAddCallback()
  - mxmlEntityGetName()
  - mxmlEntityGetValue()
  - mxmlEntityRemoveCallback()
  - mxmlFindElement()
  - mxmlIndexDelete()
  - mxmlIndexEnum()
  - mxmlIndexFind()
  - mxmlIndexNew()
  - mxmlIndexReset()
  - mxmlLoadFd()
  - mxmlLoadFile()
  - mxmlLoadString()
  - mxmlNewCustom()
  - mxmlNewElement()
  - mxmlNewInteger()
  - mxmlNewOpaque()
  - mxmlNewReal()
  - mxmlNewText()
  - mxmlNewTextf()
  - mxmlRemove()
  - mxmlSaveAllocString()
  - mxmlSaveFd()
  - mxmlSaveFile()
  - mxmlSaveString()
  - mxmlSetCustom()
  - mxmlSetCustomHandlers()
  - mxmlSetElement()
  - mxmlSetErrorCallback()
  - mxmlSetInteger()
  - mxmlSetOpaque()
  - mxmlSetReal()
  - mxmlSetText()
  - mxmlSetTextf()
  - mxmlWalkNext()
  - mxmlWalkPrev()
- Structures
  - mxml_attr_s
  - mxml_custom_s
  - mxml_index_s
  - mxml_node_s
  - mxml_text_s
  - mxml_value_s
- Types
  - mxml_attr_t
  - mxml_custom_t
  - mxml_element_t
  - mxml_index_t
  - mxml_node_t
  - mxml_text_t
  - mxml_type_t
  - mxml_value_t
- Unions
  - mxml_value_u

# Introduction

This programmers manual describes Mini-XML version 2.2.1, a small XML parsing library that you can use to read and write XML and XML-like data files in your application without requiring large non-standard libraries. Mini-XML only requires an ANSI C compatible compiler (GCC works, as do most vendors' ANSI C compilers) and a "make" program.

Mini-XML provides the following functionality:

- Reading of UTF-8 and UTF-16 encoded XML files and strings.
- Writing of UTF-8 encoded XML files and strings.
- Data is stored in a linked-list tree structure, preserving the XML data hierarchy.
- Supports arbitrary element names, attributes, and attribute values with no preset limits, just available memory.
- Supports integer, real, opaque ("cdata"), and text data types in "leaf" nodes.
- Functions for creating and managing trees of data.
- "Find" and "walk" functions for easily locating and navigating trees of data.

Mini-XML doesn't do validation or other types of processing on the data based upon schema files or other sources of definition information, nor does it support character entities other than those required by the XML specification.

## Legal Stuff

The Mini-XML library is copyright 2003-2005 by Michael Sweet.

This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details.

## History

Mini-XML was initially developed for the Gimp-Print project to replace the rather large and unwieldy `libxml2` library with something substantially smaller and easier-to-use. It all began one morning in June of 2003 when Robert posted the following sentence to the developer's list:

> It's bad enough that we require libxml2, but rolling our own XML parser is a bit more than we can handle.

I then replied with:

> Given the limited scope of what you use in XML, it should be trivial to code a mini-XML API in a few hundred lines of code.

I took my own challenge and coded furiously for two days to produced the initial public release of Mini-XML, total lines of code: 696. Robert promptly integrated Mini-XML into Gimp-Print and removed libxml2.

Thanks to lots of feedback and support from various developers, Mini-XML has evolved since then to provide a more complete XML implementation and now stands at a whopping 2,974 lines of code, compared to 103,893 lines of code for libxml2 version 2.6.9. Aside from Gimp-Print, Mini-XML is used for the following projects/software applications:

- Common UNIX Printing System
- CUPS Driver Development Kit
- ESP Print Pro
- ZynAddSubFX

Please email me (mxml @ easysw . com) if you would like your project added or removed from this list, or if you have any comments/quotes you would like me to publish about your experiences with Mini-XML.

## Organization of This Document

This manual is organized into the following chapters and appendices:

- Chapter 1, "Building, Installing, and Packaging Mini-XML", provides compilation, installation, and packaging instructions for Mini-XML.
- Chapter 2, "Getting Started with Mini-XML", shows how to use the Mini-XML library in your programs.
- Chapter 3, "More Mini-XML Programming Techniques ", shows additional ways to use the Mini-XML library.
- Chapter 4, "Using the mxmldoc Utility", describes how to use the `mxmldoc(1)` program to generate software documentation.
- Appendix A, "GNU Library General Public License ", provides the terms and conditions for using and distributing Mini-XML.
- Appendix B, "Release Notes", lists the changes in each release of Mini-XML.
- Appendix C, "Library Reference", contains a complete reference for Mini-XML, generated by `mxmldoc`.

## Notation Conventions

Various font and syntax conventions are used in this guide. Examples and their meanings and uses are explained below:

Example |  | Description
`lpstat` `lpstat(1)` |  | The names of commands; the first mention of a command or function in a chapter is followed by a manual page section number.
/var /usr/share/cups/data/testprint.ps |  | File and directory names.
`Request ID is Printer-123` |  | Screen output.
`lp -d printer filename ENTER` |  | Literal user input; special keys like `ENTER` are in ALL CAPS.
12.3 |  | Numbers in the text are written using the period (.) to indicate the decimal point.

## Abbreviations

The following abbreviations are used throughout this manual:

> Gb
>   Gigabytes, or 1073741824 bytes
> kb
>   Kilobytes, or 1024 bytes
> Mb
>   Megabytes, or 1048576 bytes
> UTF-8, UTF-16
>   Unicode Transformation Format, 8-bit or 16-bit
> W3C
>   World Wide Web Consortium
> XML
>   Extensible Markup Language

## Other References

> The Unicode Standard, Version 4.0, Addison-Wesley, ISBN 0-321-18578-1
>   The definition of the Unicode character set which is used for XML.
> Extensible Markup Language (XML) 1.0 (Third Edition)
>   The XML specification from the World Wide Web Consortium (W3C)

# 1 - Building, Installing, and Packaging Mini-XML

This chapter describes how to build, install, and package Mini-XML on your system.

## Compiling Mini-XML

Mini-XML comes with an autoconf-based configure script; just type the following command to get things going:

        ./configure ENTER

The default install prefix is /usr/local, which can be overridden using the `--prefix` option:

        ./configure --prefix=/foo ENTER

Other configure options can be found using the `--help` option:

        ./configure --help ENTER

Once you have configured the software, use the `make(1)` program to do the build and run the test program to verify that things are working, as follows:

        make ENTER

## Installing Mini-XML

Use the `make` command with the `install` target to install Mini-XML in the configured directories:

        make install ENTER

If you are using Mini-XML under Microsoft Windows with Visual C++, use the included project files in the vcnet subdirectory to build the library instead.

## Creating Mini-XML Packages

Mini-XML includes two files that can be used to create binary packages. The first file is mxml.spec which is used by the `rpmbuild(8)` software to create Red Hat Package Manager ("RPM") packages which are commonly used on Linux. Since `rpmbuild` wants to compile the software on its own, you can provide it with the Mini-XML tar file to build the package:

        rpmbuild -ta mxml-version.tar.gz ENTER

The second file is mxml.list which is used by the `epm(1)` program to create software packages in a variety of formats. The `epm` program is available from the following URL:

        http://www.easysw.com/epm/

Use the `make` command with the `epm` target to create portable and native packages for your system:

        make epm ENTER

The packages are stored in a subdirectory named dist for your convenience. The portable packages utilize scripts and tar files to install the software on the target system; this is especially useful when installing on systems with different Linux distributions. Use the mxml.install script to install the software and mxml.remove script to remove the software.

The native packages will be in the local OS's native format: RPM for Red Hat Linux, DPKG for Debian Linux, PKG for Solaris, and so forth. Use the corresponding commands to install the native packages.

# 2 - Getting Started with Mini-XML

This chapter describes how to write programs that use Mini-XML to access data in an XML file.

## The Basics

Mini-XML provides a single header file which you include:

        #include <mxml.h>

The Mini-XML library is included with your program using the `-lmxml` option:

        gcc -o myprogram myprogram.c -lmxml ENTER

If you have the `pkg-config(1)` software installed, you can use it to determine the proper compiler and linker options for your installation:

        pkg-config --cflags mxml ENTER
        pkg-config --libs mxml ENTER

## Nodes

Every piece of information in an XML file (elements, text, numbers) is stored in memory in "nodes". Nodes are defined by the `mxml_node_t` structure. The `type` member defines the node type (element, integer, opaque, real, or text) which determines which value you want to look at in the `value` union.

New nodes can be created using the `mxmlNewElement()`, `mxmlNewInteger()`, `mxmlNewOpaque()` , `mxmlNewReal()`, and `mxmlNewText()` functions. Only elements can have child nodes, and the top node must be an element, usually "?xml".

Each node has pointers for the node above (`parent`), below (`child`), to the left (`prev`), and to the right (`next` ) of the current node. If you have an XML file like the following:

        <?xml version="1.0"?>
        <data>
            <node>val1</node>
            <node>val2</node>
            <node>val3</node>
            <group>
                <node>val4</node>
                <node>val5</node>
                <node>val6</node>
            </group>
            <node>val7</node>
            <node>val8</node>
            <node>val9</node>
        </data>

the node tree returned by `mxmlLoadFile()` would look like the following in memory:

        ?xml
          |
        data
          |
        node - node - node - group - node - node - node
          |      |      |      |       |      |      |
        val1   val2   val3     |     val7   val8   val9
                               |
                             node - node - node
                               |      |      |
                             val4   val5   val6

where "-" is a pointer to the next node and "|" is a pointer to the first child node.

Once you are done with the XML data, use the `mxmlDelete()` function to recursively free the memory that is used for a particular node or the entire tree:

        mxmlDelete(tree);

## Loading XML

You load an XML file using the `mxmlLoadFile()` function:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "r");
        tree = mxmlLoadFile(NULL, fp, MXML_NO_CALLBACK);
        fclose(fp);

The first argument specifies an existing XML parent node, if any. Normally you will pass `NULL` for this argument unless you are combining multiple XML sources. The XML file must contain a complete XML document including the `?xml` element if the parent node is `NULL`.

The second argument specifies the stdio file to read from, as opened by `fopen()` or `popen()`. You can also use `stdin` if you are implementing an XML filter program.

The third argument specifies a callback function which returns the value type of the immediate children for a new element node: `MXML_INTEGER`, `MXML_OPAQUE`, `MXML_REAL`, or `MXML_TEXT`. Load callbacks are described in detail in Chapter 3. The example code uses the `MXML_NO_CALLBACK` constant which specifies that all data nodes in the document contain whitespace-separated text values.

The `mxmlLoadString()` function loads XML node trees from a string:

        char buffer[8192];
        mxml_node_t *tree;

        ...
        tree = mxmlLoadString(NULL, buffer, MXML_NO_CALLBACK);

The first and third arguments are the same as used for `mxmlLoadFile()`. The second argument specifies the string or character buffer to load and must be a complete XML document including the `?xml` element if the parent node is `NULL`.

## Saving XML

You save an XML file using the `mxmlSaveFile()` function:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "w");
        mxmlSaveFile(tree, fp, MXML_NO_CALLBACK);
        fclose(fp);

The first argument is the XML node tree to save. It should normally be a pointer to the top-level `?xml` node in your XML document.

The second argument is the stdio file to write to, as opened by `fopen()` or `popen()`. You can also use `stdout` if you are implementing an XML filter program.

The third argument is the whitespace callback to use when saving the file. Whitespace callbacks are covered in detail in Chapter 3. The example code above uses the `MXML_NO_CALLBACK` constant to specify that no special whitespace handling is required.

The `mxmlSaveAllocString()` , and `mxmlSaveString()` functions save XML node trees to strings:

        char buffer[8192];
        char *ptr;
        mxml_node_t *tree;

        ...
        mxmlSaveString(tree, buffer, sizeof(buffer), MXML_NO_CALLBACK);

        ...
        ptr = mxmlSaveAllocString(tree, MXML_NO_CALLBACK);

The first and last arguments are the same as used for `mxmlSaveFile()`. The `mxmlSaveString()` function takes pointer and size arguments for saving the XML document to a fixed-size buffer, while `mxmlSaveAllocString()` returns a string buffer that was allocated using `malloc()`.

### Finding and Iterating Nodes

The `mxmlWalkPrev()` and `mxmlWalkNext()`functions can be used to iterate through the XML node tree:

        mxml_node_t *node = mxmlWalkPrev(current, tree, MXML_DESCEND);

        mxml_node_t *node = mxmlWalkNext(current, tree, MXML_DESCEND);

In addition, you can find a named element/node using the `mxmlFindElement()` function:

        mxml_node_t *node = mxmlFindElement(tree, tree, "name", "attr",
                                    	"value", MXML_DESCEND);

The `name`, `attr`, and `value` arguments can be passed as `NULL` to act as wildcards, e.g.:

        /* Find the first "a" element */
        node = mxmlFindElement(tree, tree, "a", NULL, NULL, MXML_DESCEND);

        /* Find the first "a" element with "href" attribute */
        node = mxmlFindElement(tree, tree, "a", "href", NULL, MXML_DESCEND);

        /* Find the first "a" element with "href" to a URL */
        node = mxmlFindElement(tree, tree, "a", "href",
                    	   "http://www.easysw.com/~mike/mxml/", MXML_DESCEND);

        /* Find the first element with a "src" attribute*/
        node = mxmlFindElement(tree, tree, NULL, "src", NULL, MXML_DESCEND);

        /* Find the first element with a "src" = "foo.jpg" */
        node = mxmlFindElement(tree, tree, NULL, "src", "foo.jpg", MXML_DESCEND);

You can also iterate with the same function:

        mxml_node_t *node;

        for (node = mxmlFindElement(tree, tree, "name", NULL, NULL, MXML_DESCEND);
             node != NULL;
             node = mxmlFindElement(node, tree, "name", NULL, NULL, MXML_DESCEND))
        {
          ... do something ...
        }

The `MXML_DESCEND` argument can actually be one of three constants:

- `MXML_NO_DESCEND` means to not to look at any child nodes in the element hierarchy, just look at siblings at the same level or parent nodes until the top node or top-of-tree is reached. The previous node from "group" would be the "node" element to the left, while the next node from "group" would be the "node" element to the right.
- `MXML_DESCEND_FIRST` means that it is OK to descend to the first child of a node, but not to descend further when searching. You'll normally use this when iterating through direct children of a parent node, e.g. all of the "node" elements under the "?xml" parent node in the example above. This mode is only applicable to the search function; the walk functions treat this as `MXML_DESCEND` since every call is a first time.
- `MXML_DESCEND` means to keep descending until you hit the bottom of the tree. The previous node from "group" would be the "val3" node and the next node would be the first node element under "group". If you were to walk from the root node "?xml" to the end of the tree with `mxmlWalkNext()`, the order would be:

          ?xml
          data
          node
          val1
          node
          val2
          node
          val3
          group
          node
          val4
          node
          val5
          node
          val6
          node
          val7
          node
          val8
          node
          val9

  If you started at "val9" and walked using `mxmlWalkPrev()`, the order would be reversed, ending at "?xml".

# 3 - More Mini-XML Programming Techniques

This chapter shows additional ways to use the Mini-XML library in your programs.

## Load Callbacks

Chapter 2 introduced the `mxmlLoadFile()` and `mxmlLoadString()` functions. The last argument to these functions is a callback function which is used to determine the value type of each data node in an XML document.

Mini-XML defines several standard callbacks for simple XML data files:

- `MXML_INTEGER_CALLBACK` - All data nodes contain whitespace-separated integers.
- `MXML_OPAQUE_CALLBACK` - All data nodes contain opaque strings ("CDATA").
- `MXML_REAL_CALLBACK` - All data nodes contain whitespace-separated floating-point numbers.
- `MXML_TEXT_CALLBACK` - All data nodes contain whitespace-separated strings.

You can provide your own callback functions for more complex XML documents. Your callback function will receive a pointer to the current element node and must return the value type of the immediate children for that element node: `MXML_INTEGER`, `MXML_OPAQUE`, `MXML_REAL`, or `MXML_TEXT`. The function is called after the element and its attributes have been read, so you can look at the element name, attributes, and attribute values to determine the proper value type to return.

The following callback function looks for an attribute named "type" or the element name to determine the value type for its child nodes:

        /*
         * 'type_cb()' - XML data type callback for mxmlLoadFile()...
         */

        mxml_type_t                             /* O - Data type */
        type_cb(mxml_node_t *node)              /* I - Element node */
        {
          const char    *type;                  /* Type string */

         /*
          * You can lookup attributes and/or use the element name, hierarchy, etc...
          */

          if ((type = mxmlElementGetAttr(node, "type")) == NULL)
    	type = node->value.element.name;

          if (!strcmp(type, "integer"))
    	return (MXML_INTEGER);
          else if (!strcmp(type, "opaque"))
    	return (MXML_OPAQUE);
          else if (!strcmp(type, "real"))
    	return (MXML_REAL);
          else
    	return (MXML_TEXT);
        }

To use this callback function, simply use the name when you call any of the load functions:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "r");
        tree = mxmlLoadFile(NULL, fp, type_cb);
        fclose(fp);

## Save Callbacks

Chapter 2 also introduced the `mxmlSaveFile()`, `mxmlSaveString()`, and `mxmlSaveAllocString()` functions. The last argument to these functions is a callback function which is used to automatically insert whitespace in an XML document.

Your callback function will be called up to four times for each element node with a pointer to the node and a "where" value of `MXML_WS_BEFORE_OPEN`, `MXML_WS_AFTER_OPEN`, `MXML_WS_BEFORE_CLOSE`, or `MXML_WS_AFTER_CLOSE`. The callback function should return `NULL` if no whitespace should be added and the string to insert (spaces, tabs, carriage returns, and newlines) otherwise. The following whitespace callback can be used to add whitespace to XHTML output to make it more readable in a standard text editor:

        /*
         * 'whitespace_cb()' - Let the mxmlSaveFile() function know when to insert
         *                     newlines and tabs...
         */

        const char *                            /* O - Whitespace string or NULL */
        whitespace_cb(mxml_node_t *node,        /* I - Element node */
            	  int         where)        /* I - Open or close tag? */
        {
          const char *name;                     /* Name of element */

         /*
          * We can conditionally break to a new line before or after any element.
          * These are just common HTML elements...
          */

          name = node->value.element.name;

          if (!strcmp(name, "html") || !strcmp(name, "head") || !strcmp(name, "body") ||
    	  !strcmp(name, "pre") || !strcmp(name, "p") ||
    	  !strcmp(name, "h1") || !strcmp(name, "h2") || !strcmp(name, "h3") ||
    	  !strcmp(name, "h4") || !strcmp(name, "h5") || !strcmp(name, "h6"))
          {
           /*
    	* Newlines before open and after close...
    	*/

    	if (where == MXML_WS_BEFORE_OPEN || where == MXML_WS_AFTER_CLOSE)
    	  return ("\n");
          }
          else if (!strcmp(name, "dl") || !strcmp(name, "ol") || !strcmp(name, "ul"))
          {
           /*
    	* Put a newline before and after list elements...
    	*/

    	return ("\n");
          }
          else if (!strcmp(name, "dd") || !strcmp(name, "dt") || !strcmp(name, "li"))
          {
           /*
    	* Put a tab before <li>'s, <dd>'s, and <dt>'s, and a newline after them...
    	*/

    	if (where == MXML_WS_BEFORE_OPEN)
    	  return ("\t");
    	else if (where == MXML_WS_AFTER_CLOSE)
    	  return ("\n");
          }

         /*
          * Return NULL for no added whitespace...
          */

          return (NULL);
        }

To use this callback function, simply use the name when you call any of the save functions:

        FILE *fp;
        mxml_node_t *tree;

        fp = fopen("filename.xml", "w");
        mxmlSaveFile(tree, fp, whitespace_cb);
        fclose(fp);

## Custom Data Types

Mini-XML supports custom data types via global load and save callbacks. Only a single set of callbacks can be active at any time, however your callbacks can store additional information in order to support multiple custom data types as needed. The `MXML_CUSTOM` node type identifies custom data nodes.

The load callback receives a pointer to the current data node and a string of opaque character data from the XML source with character entities converted to the corresponding UTF-8 characters. For example, if we wanted to support a custom date/time type whose value is encoded as "yyyy-mm-ddThh:mm:ssZ" (ISO format), the load callback would look like the following:

        typedef struct
        {
          unsigned      year,                   /* Year */
                        month,                  /* Month */
                        day,                    /* Day */
                        hour,                   /* Hour */
                        minute,                 /* Minute */
                        second;                 /* Second */
          time_t        unix;                   /* UNIX time value */
        } iso_date_time_t;

        int                                     /* I - 0 on success, -1 on error */
        load_custom(mxml_node_t *node,          /* I - Node */
                    const char  *data)          /* I - Value */
        {
          iso_date_time_t *dt;                  /* Date/time value */
          struct tm       tmdata;               /* UNIX time data */

         /*
          * Allocate data structure...
          */

          dt = calloc(1, sizeof(iso_date_time_t));

         /*
          * Try reading 6 unsigned integers from the data string...
          */

          if (sscanf(data, "%u-%u-%uT%u:%u:%uZ",
                     &(dt->year), &(dt->month), &(dt->day),
                     &(dt->hour), &(dt->minute), &(dt->second)) != 6)
          {
           /*
            * Unable to read numbers, free the data structure and return an
            * error...
            */

            free(dt);

            return (-1);
          }

         /*
          * Range check values...
          */

          if (dt->month <1 || dt->month > 12 ||
              dt->day  <1 || dt->day > 31 ||
              dt->hour  <0 || dt->hour > 23 ||
              dt->minute  <0 || dt->minute > 59 ||
              dt->second  <0 || dt->second > 59)
          {
           /*
            * Date information is out of range...
            */

            free(dt);

            return (-1);
          }

         /*
          * Convert ISO time to UNIX time in seconds...
          */

          tmdata.tm_year = dt->year - 1900;
          tmdata.tm_mon  = dt->month - 1;
          tmdata.tm_day  = dt->day;
          tmdata.tm_hour = dt->hour;
          tmdata.tm_min  = dt->minute;
          tmdata.tm_sec  = dt->second;

          dt->unix = gmtime(&tmdata);

         /*
          * Assign custom node data and destroy function pointers...
          */

          node->value.custom.data    = dt;
          node->value.custom.destroy = free;

         /*
          * Return with no errors...
          */

          return (0);
        }

The function itself can return 0 on success or -1 if it is unable to decode the custom data or the data contains an error. Custom data nodes contain a `void` pointer to the allocated custom data for the node and a pointer to a destructor function which will free the custom data when the node is deleted.

The save callback receives the node pointer and returns an allocated string containing the custom data value. The following save callback could be used for our ISO date/time type:

        char *                                  /* I - Allocated string */
        save_custom(mxml_node_t *node)          /* I - Node */
        {
          char            data[255];            /* Data string */
          iso_date_time_t *dt;                  /* ISO date/time pointer */

          dt = (iso_date_time_t *)node->custom.data;

          snprintf(data, sizeof(data), "%04u-%02u-%02uT%02u:%02u:%02uZ",
                   dt->year, dt->month, dt->day, dt->hour,
                   dt->minute, dt->second);

          return (strdup(data));
        }

You register the callback functions using the `mxmlSetCustomHandlers()` function:

        mxmlSetCustomHandlers(load_custom, save_custom);

## Changing Node Values

All of the examples so far have concentrated on creating and loading new XML data nodes. Many applications, however, need to manipulate or change the nodes during their operation, so Mini-XML provides functions to change node values safely and without leaking memory.

Existing nodes can be changed using the `mxmlSetElement()`, `mxmlSetInteger()`, `mxmlSetOpaque()` , `mxmlSetReal()`, and `mxmlSetText()` functions. For example, use the following function call to change a text node to contain the text "new" with leading whitespace:

        mxml_node_t *node;

        mxmlSetText(node, 1, "new");

## Formatted Text

The `mxmlNewTextf()` and `mxmlSetTextf()` functions create and change text nodes, respectively, using `printf`-style format strings and arguments. For example, use the following function call to create a new text node:

        mxml_node_t *node;

        node = mxmlNewTextf(node, 1, "%s/%s",
                            path, filename);

## Indexing

Mini-XML provides functions for managing indices of nodes. The current implementation provides the same functionality as the `mxmlFindElement()`. The advantage of using an index is that searching and enumeration of elements is significantly faster. The only disadvantage is that each index is a static snapshot of the XML document, so indices are not well suited to XML data that is updated more often than it is searched. The overhead of creating an index is approximately equal to walking the XML document tree. Nodes in the index are sorted by element name and attribute value.

Indices are stored in `mxml_index_t` structures. The `mxmlIndexNew()` function creates a new index:

        mxml_node_t *tree;
        mxml_index_t *ind;

        ind = mxmlIndexNew(tree, "element", "attribute");

The first argument is the XML node tree to index. Normally this will be a pointer to the `?xml` element.

The second argument contains the element to index; passing `NULL` indexes all element nodes alphabetically.

The third argument contains the attribute to index; passing `NULL` causes only the element name to be indexed.

Once the index is created, the `mxmlIndexEnum()`, `mxmlIndexFind()` , and `mxmlIndexReset()` functions are used to access the nodes in the index. The `mxmlIndexReset()` function resets the "current" node pointer in the index, allowing you to do new searches and enumerations on the same index. Typically you will call this function prior to your calls to `mxmlIndexEnum()` and `mxmlIndexFind()`.

The `mxmlIndexEnum()` function enumerates each of the nodes in the index and can be used in a loop as follows:

        mxml_node_t *node;
        mxml_index_t *ind;

        mxmlIndexReset(ind);

        while ((node = mxmlIndexEnum(ind)) != NULL)
        {
          // do something with node
        }

The `mxmlIndexFind()` function locates the next occurrence of the named element and attribute value in the index. It can be used to find all matching elements in an index, as follows:

        mxml_node_t *node;
        mxml_index_t *ind;

        mxmlIndexReset(ind);

        while ((node = mxmlIndexFind(ind, "element", "attr-value")) != NULL)
        {
          // do something with node
        }

The second and third arguments represent the element name and attribute value, respectively. A `NULL` pointer is used to return all elements or attributes in the index. Passing `NULL` for both the element name and attribute value is equivalent to calling `mxmlIndexEnum`.

When you are done using the index, delete it using the `mxmlIndexDelete()` function:

        mxml_index_t *ind;

        mxmlIndexDelete(ind);

# 4 - Using the mxmldoc Utility

This chapter describes how to use the `mxmldoc(1)` utility that comes with Mini-XML to automatically generate documentation for your programs.

## The Basics

The `mxmldoc` utility scans C and C++ source and header files and produces an XML file describing the library interface and an XHTML file providing a human-readable reference to the code. Each source and header file must conform to some simple code commenting conventions so that `mxmldoc` can extract the necessary descriptive text.

The `mxmldoc` command requires the name of an XML file to store the code information; this file is created and updated as necessary. The XML file is optionally followed by a list of source files to scan. After scanning any source files on the command-line, `mxmldoc` writes XHTML documentation to the standard output, which can be redirected to the file using the `>filename` syntax:

        mxmldoc myfile.xml >myfile.html ENTER
        mxmldoc myfile.xml file1.c file2.cxx file3.h >myfile.html ENTER

If no source files are provided on the command-line, the current contents of the XML file are converted to XHTML.

## Code Documentation Conventions

As noted previously, source code must be commented properly for `mxmldoc` to generate correct documentation for the code. Single line comments can use the C++ `//` comment sequence, however all multi-line comments must use the C `/* ... */` comment sequence.

### Functions and Methods

All implementations of functions and methods must begin with a comment header describing what the function does, the possible input limits (if any), and the possible output values (if any), and any special information needed, as follows:

        /*
         * 'do_this()' - Compute y = this(x).
         *
         * Notes: none.
         */

        float            /* O - Inverse power value, 0.0 <= y <= 1.1 */
        do_this(float x) /* I - Power value (0.0 <= x <= 1.1) */
        {
          ...
          return (y);
        }

Return/output values are indicated using an "O" prefix, input values are indicated using the "I" prefix, and values that are both input and output use the "IO" prefix for the corresponding in-line comment.

### Variables and Class/Structure/Union Members

Each variable or member must be declared on a separate line and must be immediately followed by a comment describing the variable or member, as follows:

        int this_variable;   /* The current state of this */
        int that_variable;   /* The current state of that */

### Types

Each type must have a comment block immediately before the typedef, as follows:

        /*
         * This type is for foobar options.
         */
        typedef int this_type_t;

### Classes, Structures, and Unions

Each class, structure, and union must have a comment block immediately before the definition, and each member must be documented in accordance with the function and variable documentation requirements, as follows:

        /*
         * This structure is for foobar options.
         */
        struct this_struct_s
        {
          int this_member;   /* Current state for this */
          int that_member;   /* Current state for that */
        };

        /*
         * This class is for barfoo options.
         */
        class this_class_c
        {
          int this_member;   /* Current state for this */
          int that_member;   /* Current state for that */

          /*
           * 'get_this()' - Get the current state for this.
           */
          int                /* O - Current state for this */
          get_this()
          {
            return (this_member);
          }
        };

### Enumerations

Each enumeration must have a comment block immediately before the definition describing what the enumeration is for, and each enumeration value must have a comment immediately after the value, as follows:

       /*
        * Enumeration of media trays.
        */
        enum this_enum_e
        {
          THIS_TRAY,   /* This tray */
          THAT_TRAY    /* That tray */
        };

## XML Schema

Listing 4-1 shows the XML schema file mxmldoc.xsd which is included with Mini-XML. This schema file can be used to convert the XML files produced by `mxmldoc` into other formats.

Listing 4-1, XML Schema File "mxmldoc.xsd"
    <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
      <xsd:annotation>
        <xsd:documentation xml:lang="en">
          Mini-XML 2.2 documentation schema for mxmldoc output.
          Copyright 2003-2005 by Michael Sweet.

          This program is free software; you can redistribute it and/or
          modify it under the terms of the GNU Library General Public
          License as published by the Free Software Foundation; either
          version 2, or (at your option) any later version.

          This program is distributed in the hope that it will be useful,
          but WITHOUT ANY WARRANTY; without even the implied warranty of
          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
          GNU General Public License for more details.
        </xsd:documentation>
      </xsd:annotation>

      <!-- basic element definitions -->
      <xsd:element name="argument" type="argumentType"/>
      <xsd:element name="class" type="classType"/>
      <xsd:element name="constant" type="constantType"/>
      <xsd:element name="description" type="xsd:string"/>
      <xsd:element name="enumeration" type="enumerationType"/>
      <xsd:element name="function" type="functionType"/>
      <xsd:element name="mxmldoc" type="mxmldocType"/>
      <xsd:element name="namespace" type="namespaceType"/>
      <xsd:element name="returnvalue" type="returnvalueType"/>
      <xsd:element name="seealso" type="identifierList"/>
      <xsd:element name="struct" type="structType"/>
      <xsd:element name="typedef" type="typedefType"/>
      <xsd:element name="type" type="xsd:string"/>
      <xsd:element name="union" type="unionType"/>
      <xsd:element name="variable" type="variableType"/>

      <!-- descriptions of complex elements -->
      <xsd:complexType name="argumentType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="default" type="xsd:string" use="optional"/>
        <xsd:attribute name="name" type="identifier" use="required"/>
        <xsd:attribute name="direction" type="direction" use="optional" default="I"/>
      </xsd:complexType>

      <xsd:complexType name="classType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:choice minOccurs="0" maxOccurs="unbounded">
    	<xsd:element ref="class"/>

Listing 4-1, XML Schema File "mxmldoc.xsd" (con't)
    	<xsd:element ref="enumeration"/>
    	<xsd:element ref="function"/>
    	<xsd:element ref="struct"/>
    	<xsd:element ref="typedef"/>
    	<xsd:element ref="union"/>
    	<xsd:element ref="variable"/>
          </xsd:choice>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
        <xsd:attribute name="parent" type="xsd:string" use="optional"/>
      </xsd:complexType>

      <xsd:complexType name="constantType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="enumerationType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="constant" minOccurs="1" maxOccurs="unbounded"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="functionType">
        <xsd:sequence>
          <xsd:element ref="returnvalue" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="argument" minOccurs="1" maxOccurs="unbounded"/>
          <xsd:element ref="seealso" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
        <xsd:attribute name="scope" type="scope" use="optional"/>
      </xsd:complexType>

      <xsd:complexType name="mxmldocType">
        <xsd:choice minOccurs="0" maxOccurs="unbounded">
          <xsd:element ref="class"/>
          <xsd:element ref="enumeration"/>
          <xsd:element ref="function"/>
          <xsd:element ref="namespace"/>
          <xsd:element ref="struct"/>
          <xsd:element ref="typedef"/>
          <xsd:element ref="union"/>
          <xsd:element ref="variable"/>
        </xsd:choice>
      </xsd:complexType>

      <xsd:complexType name="namespaceType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:choice minOccurs="0" maxOccurs="unbounded">
    	<xsd:element ref="class"/>
    	<xsd:element ref="enumeration"/>
    	<xsd:element ref="function"/>

Listing 4-1, XML Schema File "mxmldoc.xsd" (con't)
    	<xsd:element ref="struct"/>
    	<xsd:element ref="typedef"/>
    	<xsd:element ref="union"/>
    	<xsd:element ref="variable"/>
          </xsd:choice>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="returnvalueType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
      </xsd:complexType>

      <xsd:complexType name="structType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:choice minOccurs="0" maxOccurs="unbounded">
    	<xsd:element ref="variable"/>
    	<xsd:element ref="function"/>
          </xsd:choice>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="typedefType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="unionType">
        <xsd:sequence>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
          <xsd:element ref="variable" minOccurs="0" maxOccurs="unbounded"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <xsd:complexType name="variableType">
        <xsd:sequence>
          <xsd:element ref="type" minOccurs="1" maxOccurs="1"/>
          <xsd:element ref="description" minOccurs="0" maxOccurs="1"/>
        </xsd:sequence>
        <xsd:attribute name="name" type="identifier" use="required"/>
      </xsd:complexType>

      <!-- data types -->
      <xsd:simpleType name="direction">
        <xsd:restriction base="xsd:string">
          <xsd:enumeration value="I"/>
          <xsd:enumeration value="O"/>
          <xsd:enumeration value="IO"/>
        </xsd:restriction>

Listing 4-1, XML Schema File "mxmldoc.xsd" (con't)
      </xsd:simpleType>

      <xsd:simpleType name="identifier">
        <xsd:restriction base="xsd:string">
          <xsd:pattern value="[a-zA-Z_(.]([a-zA-Z_(.,)* 0-9])*"/>
        </xsd:restriction>
      </xsd:simpleType>

      <xsd:simpleType name="identifierList">
        <xsd:list itemType="identifier"/>
      </xsd:simpleType>

      <xsd:simpleType name="scope">
        <xsd:restriction base="xsd:string">
          <xsd:enumeration value=""/>
          <xsd:enumeration value="private"/>
          <xsd:enumeration value="protected"/>
          <xsd:enumeration value="public"/>
        </xsd:restriction>
      </xsd:simpleType>
    </xsd:schema>

# A - GNU Library General Public License

Version 2, June 1991
Copyright (C) 1991 Free Software Foundation, Inc.
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.
[This is the first released version of the library GPL. It is numbered 2 because it goes with version 2 of the ordinary GPL.]

Preamble

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This section is intended to make thoroughly clear what is believed to be a consequence of the rest of this License.

12. If the distribution and/or use of the Library is restricted in certain countries either by patents or by copyrighted interfaces, the original copyright holder who places the Library under this License may add an explicit geographical distribution limitation excluding those countries, so that distribution is permitted only in or among countries not thus excluded. In such case, this License incorporates the limitation as if written in the body of this License.

13. The Free Software Foundation may publish revised and/or new versions of the Library General Public License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns.

Each version is given a distinguishing version number. If the Library specifies a version number of this License which applies to it and "any later version", you have the option of following the terms and conditions either of that version or of any later version published by the Free Software Foundation. If the Library does not specify a license version number, you may choose any version ever published by the Free Software Foundation.

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NO WARRANTY

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END OF TERMS AND CONDITIONS

## How to Apply These Terms to Your New Libraries

If you develop a new library, and you want it to be of the greatest possible use to the public, we recommend making it free software that everyone can redistribute and change. You can do so by permitting redistribution under these terms (or, alternatively, under the terms of the ordinary General Public License).

To apply these terms, attach the following notices to the library. It is safest to attach them to the start of each source file to most effectively convey the exclusion of warranty; and each file should have at least the "copyright" line and a pointer to where the full notice is found.

    one line to give the library's name and an idea of what it does.
    Copyright (C) year  name of author

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

Also add information on how to contact you by electronic and paper mail.

You should also get your employer (if you work as a programmer) or your school, if any, to sign a "copyright disclaimer" for the library, if necessary. Here is a sample; alter the names:

    Yoyodyne, Inc., hereby disclaims all copyright interest in
    the library `Frob' (a library for tweaking knobs) written
    by James Random Hacker.

    signature of Ty Coon, 1 April 1990
    Ty Coon, President of Vice

That's all there is to it!

# B - Release Notes

## Changes in Mini-XML 2.2.2

- mxmlLoad*() did not treat custom data as opaque, so whitespace characters would be lost.

## Changes in Mini-XML 2.2.1

- mxmlLoadFd(), mxmlLoadFile(), and mxmlLoadString() now correctly return NULL on error (STR #21)
- mxmlNewInteger(), mxmlNewOpaque(), mxmlNewReal(), mxmlNewText(), and mxmlNewTextf() incorrectly required a parent node (STR #22)
- Fixed an XML output bug in mxmldoc.
- The "make install" target now uses the install command to set the proper permissions on UNIX/Linux/OSX.
- Fixed a MingW/Cygwin compilation problem (STR #18)

## Changes in Mini-XML 2.2

- Added shared library support (STR #17)
- mxmlLoad*() now returns an error when an XML stream contains illegal control characters (STR #10)
- mxmlLoad*() now returns an error when an element contains two attributes with the same name in conformance with the XML spec (STR #16)
- Added support for CDATA (STR #14, STR #15)
- Updated comment and processing instruction handling - no entity support per XML specification.
- Added checking for invalid comment termination ("--->" is not allowed)

## Changes in Mini-XML 2.1

- Added support for custom data nodes (STR #6)
- Now treat UTF-8 sequences which are longer than necessary as an error (STR #4)
- Fixed entity number support (STR #8)
- Fixed mxmlLoadString() bug with UTF-8 (STR #7)
- Fixed entity lookup bug (STR #5)
- Added mxmlLoadFd() and mxmlSaveFd() functions.
- Fixed multi-word UTF-16 handling.

## Changes in Mini-XML 2.0

- New programmers manual.
- Added Visual C++ project files for Microsoft Windows users.
- Added optimizations to mxmldoc, mxmlSaveFile(), and mxmlIndexNew() (STR #2)
- mxmlEntityAddCallback() now returns an integer status (STR #2)
- Added UTF-16 support (input only; all output is UTF-8)
- Added index functions to build a searchable index of XML nodes.
- Added character entity callback interface to support additional character entities beyond those defined in the XHTML specification.
- Added support for XHTML character entities.
- The mxmldoc utility now produces XML output which conforms to an updated XML schema, described in the file "doc/mxmldoc.xsd".
- Changed the whitespace callback interface to return strings instead of a single character, allowing for greater control over the formatting of XML files written using Mini-XML. THIS CHANGE WILL REQUIRE CHANGES TO YOUR 1.x CODE IF YOU USE WHITESPACE CALLBACKS.
- The mxmldoc utility now produces XML output which conforms to an updated XML schema, described in the file "doc/mxmldoc.xsd".
- Changed the whitespace callback interface to return strings instead of a single character, allowing for greater control over the formatting of XML files written using Mini-XML. THIS CHANGE WILL REQUIRE CHANGES TO YOUR 1.x CODE IF YOU USE WHITESPACE CALLBACKS.
- The mxmldoc utility is now capable of documenting C++ classes, functions, and structures, and correctly handles C++ comments.
- Added new modular tests for mxmldoc.
- Updated the mxmldoc output to be more compatible with embedding in manuals produced with HTMLDOC.
- The makefile incorrectly included a "/" separator between the destination path and install path. This caused problems when building and installing with MingW.

## Changes in Mini-XML 1.3

- Fixes for mxmldoc.
- Added support for reading standard HTML entity names.
- mxmlLoadString/File() did not decode character entities in element names, attribute names, or attribute values.
- mxmlLoadString/File() would crash when loading non- conformant XML data under an existing parent (top) node.
- Fixed several bugs in the mxmldoc utility.
- Added new error callback function to catch a variety of errors and log them to someplace other than stderr.
- The mxmlElementSetAttr() function now allows for NULL attribute values.
- The load and save functions now properly handle quoted element and attribute name strings properly, e.g. for !DOCTYPE declarations.

## Changes in Mini-XML 1.2

- Added new "set" methods to set the value of a node.
- Added new formatted text methods mxmlNewTextf() and mxmlSetTextf() to create/set a text node value using printf-style formats.
- Added new standard callbacks for use with the mxmlLoad functions.
- Updated the HTML documentation to include examples of the walk and load function output.
- Added --with/without-ansi configure option to control the strdup() function check.
- Added --with/without-snprintf configure option to control the snprintf() and vsnprintf() function checks.

## Changes in Mini-XML 1.1.2

- The mxml(3) man page wasn't updated for the string functions.
- mxmlSaveString() returned the wrong number of characters.
- mxml_add_char() updated the buffer pointer in the wrong place.

## Changes in Mini-XML 1.1.1

- The private mxml_add_ch() function did not update the start-of-buffer pointer which could cause a crash when using mxmlSaveString().
- The private mxml_write_ws() function called putc() instead of using the proper callback which could cause a crash when using mxmlSaveString().
- Added a mxmlSaveAllocString() convenience function for saving an XML node tree to an allocated string.

## Changes in Mini-XML 1.1

- The mxmlLoadFile() function now uses dynamically allocated string buffers for element names, attribute names, and attribute values. Previously they were capped at 16383, 255, and 255 bytes, respectively.
- Added a new mxmlLoadString() function for loading an XML node tree from a string.
- Added a new mxmlSaveString() function for saving an XML node tree to a string.
- Add emulation of strdup() if the local platform does not provide the function.

## Changes in Mini-XML 1.0

- The mxmldoc program now handles function arguments, structures, unions, enumerations, classes, and typedefs properly.
- Documentation provided via mxmldoc and more in-line comments in the code.
- Added man pages and packaging files.

## Changes in Mini-XML 0.93

- New mxmldoc example program that is also used to create and update code documentation using XML and produce HTML reference pages.
- Added mxmlAdd() and mxmlRemove() functions to add and remove nodes from a tree. This provides more flexibility over where the nodes are inserted and allows nodes to be moved within the tree as needed.
- mxmlLoadFile() now correctly handles comments.
- mxmlLoadFile() now supports the required "gt", "quot", and "nbsp" character entities.
- mxmlSaveFile() now uses newlines as whitespace when valid to do so.
- mxmlFindElement() now also takes attribute name and attribute value string arguments to limit the search to specific elements with attributes and/or values.
NULL pointers can be used as "wildcards".
- Added uninstall target to makefile, and auto-reconfig if Makefile.in or configure.in are changed.
- mxmlFindElement(), mxmlWalkNext(), and mxmlWalkPrev() now all provide "descend" arguments to control whether they descend into child nodes in the tree.
- Fixed some whitespace issues in mxmlLoadFile().
- Fixed Unicode output and whitespace issues in mxmlSaveFile().
- mxmlSaveFile() now supports a whitespace callback to provide more human-readable XML output under program control.

## Changes in Mini-XML 0.92

- mxmlSaveFile() didn't return a value on success.

## Changes in Mini-XML 0.91

- mxmlWalkNext() would go into an infinite loop.

## Changes in Mini-XML 0.9

- Initial public release.

# C - Library Reference

## Contents

- Enumerations
- Functions
- Structures
- Types
- Unions

## Enumerations

- `mxml_type_e`

### mxml_type_e

#### Description

The XML node type.

#### Values

Name | Description
--- | ---
`MXML_CUSTOM` | Custom data
`MXML_ELEMENT` | XML element with attributes
`MXML_INTEGER` | Integer value
`MXML_OPAQUE` | Opaque string
`MXML_REAL` | Real value
`MXML_TEXT` | Text fragment

## Functions

- `mxmlAdd()`
- `mxmlDelete()`
- `mxmlElementGetAttr()`
- `mxmlElementSetAttr()`
- `mxmlEntityAddCallback()`
- `mxmlEntityGetName()`
- `mxmlEntityGetValue()`
- `mxmlEntityRemoveCallback()`
- `mxmlFindElement()`
- `mxmlIndexDelete()`
- `mxmlIndexEnum()`
- `mxmlIndexFind()`
- `mxmlIndexNew()`
- `mxmlIndexReset()`
- `mxmlLoadFd()`
- `mxmlLoadFile()`
- `mxmlLoadString()`
- `mxmlNewCustom()`
- `mxmlNewElement()`
- `mxmlNewInteger()`
- `mxmlNewOpaque()`
- `mxmlNewReal()`
- `mxmlNewText()`
- `mxmlNewTextf()`
- `mxmlRemove()`
- `mxmlSaveAllocString()`
- `mxmlSaveFd()`
- `mxmlSaveFile()`
- `mxmlSaveString()`
- `mxmlSetCustom()`
- `mxmlSetCustomHandlers()`
- `mxmlSetElement()`
- `mxmlSetErrorCallback()`
- `mxmlSetInteger()`
- `mxmlSetOpaque()`
- `mxmlSetReal()`
- `mxmlSetText()`
- `mxmlSetTextf()`
- `mxmlWalkNext()`
- `mxmlWalkPrev()`

### mxmlAdd()

#### Description

Add a node to a tree. Adds the specified node to the parent. If the child argument is not NULL, puts the new node before or after the specified child depending on the value of the where argument. If the child argument is NULL, puts the new node at the beginning of the child list (MXML_ADD_BEFORE) or at the end of the child list (MXML_ADD_AFTER). The constant MXML_ADD_TO_PARENT can be used to specify a NULL child pointer.

#### Syntax

    void
    mxmlAdd(
        mxml_node_t * parent,
        int where,
        mxml_node_t * child,
        mxml_node_t * node);

#### Arguments

Name | Description
--- | ---
`parent` | Parent node
`where` | Where to add, MXML_ADD_BEFORE or MXML_ADD_AFTER
`child` | Child node for where or MXML_ADD_TO_PARENT
`node` | Node to add

#### Returns

Nothing.

### mxmlDelete()

#### Description

Delete a node and all of its children. If the specified node has a parent, this function first removes the node from its parent using the mxmlRemove() function.

#### Syntax

    void
    mxmlDelete(
        mxml_node_t * node);

#### Arguments

Name | Description
--- | ---
`node` | Node to delete

#### Returns

Nothing.

### mxmlElementGetAttr()

#### Description

Get an attribute. This function returns NULL if the node is not an element or the named attribute does not exist.

#### Syntax

    const char *
    mxmlElementGetAttr(
        mxml_node_t * node,
        const char * name);

#### Arguments

Name | Description
--- | ---
`node` | Element node
`name` | Name of attribute

#### Returns

Attribute value or NULL

### mxmlElementSetAttr()

#### Description

Set an attribute. If the named attribute already exists, the value of the attribute is replaced by the new string value. The string value is copied into the element node. This function does nothing if the node is not an element.

#### Syntax

    void
    mxmlElementSetAttr(
        mxml_node_t * node,
        const char * name,
        const char * value);

#### Arguments

Name | Description
--- | ---
`node` | Element node
`name` | Name of attribute
`value` | Attribute value

#### Returns

Nothing.

### mxmlEntityAddCallback()

#### Description

Add a callback to convert entities to Unicode.

#### Syntax

    int
    mxmlEntityAddCallback(
        int (*cb)(const char *name));

#### Arguments

Name | Description
--- | ---
`(*cb)(const char *name)` | Callback function to add

#### Returns

0 on success, -1 on failure

### mxmlEntityGetName()

#### Description

Get the name that corresponds to the character value. If val does not need to be represented by a named entity, NULL is returned.

#### Syntax

    const char *
    mxmlEntityGetName(
        int val);

#### Arguments

Name | Description
--- | ---
`val` | Character value

#### Returns

Entity name or NULL

### mxmlEntityGetValue()

#### Description

Get the character corresponding to a named entity. The entity name can also be a numeric constant. -1 is returned if the name is not known.

#### Syntax

    int
    mxmlEntityGetValue(
        const char * name);

#### Arguments

Name | Description
--- | ---
`name` | Entity name

#### Returns

Character value or -1 on error

### mxmlEntityRemoveCallback()

#### Description

Remove a callback.

#### Syntax

    void
    mxmlEntityRemoveCallback(
        int (*cb)(const char *name));

#### Arguments

Name | Description
--- | ---
`(*cb)(const char *name)` | Callback function to remove

#### Returns

Nothing.

### mxmlFindElement()

#### Description

Find the named element. The search is constrained by the name, attribute name, and value; any NULL names or values are treated as wildcards, so different kinds of searches can be implemented by looking for all elements of a given name or all elements with a specific attribute. The descend argument determines whether the search descends into child nodes; normally you will use MXML_DESCEND_FIRST for the initial search and MXML_NO_DESCEND to find additional direct descendents of the node. The top node argument constrains the search to a particular node's children.

#### Syntax

    mxml_node_t *
    mxmlFindElement(
        mxml_node_t * node,
        mxml_node_t * top,
        const char * name,
        const char * attr,
        const char * value,
        int descend);

#### Arguments

Name | Description
--- | ---
`node` | Current node
`top` | Top node
`name` | Element name or NULL for any
`attr` | Attribute name, or NULL for none
`value` | Attribute value, or NULL for any
`descend` | Descend into tree - MXML_DESCEND, MXML_NO_DESCEND, or MXML_DESCEND_FIRST

#### Returns

Element node or NULL

### mxmlIndexDelete()

#### Description

Delete an index.

#### Syntax

    void
    mxmlIndexDelete(
        mxml_index_t * ind);

#### Arguments

Name | Description
--- | ---
`ind` | Index to delete

#### Returns

Nothing.

### mxmlIndexEnum()

#### Description

Return the next node in the index. Nodes are returned in the sorted order of the index.

#### Syntax

    mxml_node_t *
    mxmlIndexEnum(
        mxml_index_t * ind);

#### Arguments

Name | Description
--- | ---
`ind` | Index to enumerate

#### Returns

Next node or NULL if there is none

### mxmlIndexFind()

#### Description

Find the next matching node. You should call mxmlIndexReset() prior to using this function for the first time with a particular set of "element" and "value" strings. Passing NULL for both "element" and "value" is equivalent to calling mxmlIndexEnum().

#### Syntax

    mxml_node_t *
    mxmlIndexFind(
        mxml_index_t * ind,
        const char * element,
        const char * value);

#### Arguments

Name | Description
--- | ---
`ind` | Index to search
`element` | Element name to find, if any
`value` | Attribute value, if any

#### Returns

Node or NULL if none found

### mxmlIndexNew()

#### Description

Create a new index. The index will contain all nodes that contain the named element and/or attribute. If both "element" and "attr" are NULL, then the index will contain a sorted list of the elements in the node tree. Nodes are sorted by element name and optionally by attribute value if the "attr" argument is not NULL.

#### Syntax

    mxml_index_t *
    mxmlIndexNew(
        mxml_node_t * node,
        const char * element,
        const char * attr);

#### Arguments

Name | Description
--- | ---
`node` | XML node tree
`element` | Element to index or NULL for all
`attr` | Attribute to index or NULL for none

#### Returns

New index

### mxmlIndexReset()

#### Description

Reset the enumeration/find pointer in the index and return the first node in the index. This function should be called prior to using mxmlIndexEnum() or mxmlIndexFind() for the first time.

#### Syntax

    mxml_node_t *
    mxmlIndexReset(
        mxml_index_t * ind);

#### Arguments

Name | Description
--- | ---
`ind` | Index to reset

#### Returns

First node or NULL if there is none

### mxmlLoadFd()

#### Description

Load a file descriptor into an XML node tree. The nodes in the specified file are added to the specified top node. If no top node is provided, the XML file MUST be well-formed with a single parent node like <?xml> for the entire file. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes. The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.

#### Syntax

    mxml_node_t *
    mxmlLoadFd(
        mxml_node_t * top,
        int fd,
        mxml_type_t (*cb)(mxml_node_t *node));

#### Arguments

Name | Description
--- | ---
`top` | Top node
`fd` | File descriptor to read from
`(*cb)(mxml_node_t *node)` | Callback function or MXML_NO_CALLBACK

#### Returns

First node or NULL if the file could not be read.

### mxmlLoadFile()

#### Description

Load a file into an XML node tree. The nodes in the specified file are added to the specified top node. If no top node is provided, the XML file MUST be well-formed with a single parent node like <?xml> for the entire file. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes. The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.

#### Syntax

    mxml_node_t *
    mxmlLoadFile(
        mxml_node_t * top,
        FILE * fp,
        mxml_type_t (*cb)(mxml_node_t *node));

#### Arguments

Name | Description
--- | ---
`top` | Top node
`fp` | File to read from
`(*cb)(mxml_node_t *node)` | Callback function or MXML_NO_CALLBACK

#### Returns

First node or NULL if the file could not be read.

### mxmlLoadString()

#### Description

Load a string into an XML node tree. The nodes in the specified string are added to the specified top node. If no top node is provided, the XML string MUST be well-formed with a single parent node like <?xml> for the entire string. The callback function returns the value type that should be used for child nodes. If MXML_NO_CALLBACK is specified then all child nodes will be either MXML_ELEMENT or MXML_TEXT nodes. The constants MXML_INTEGER_CALLBACK, MXML_OPAQUE_CALLBACK, MXML_REAL_CALLBACK, and MXML_TEXT_CALLBACK are defined for loading child nodes of the specified type.

#### Syntax

    mxml_node_t *
    mxmlLoadString(
        mxml_node_t * top,
        const char * s,
        mxml_type_t (*cb)(mxml_node_t *node));

#### Arguments

Name | Description
--- | ---
`top` | Top node
`s` | String to load
`(*cb)(mxml_node_t *node)` | Callback function or MXML_NO_CALLBACK

#### Returns

First node or NULL if the string has errors.

### mxmlNewCustom()

#### Description

Create a new custom data node. The new custom node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new element node has no parent. NULL can be passed when the data in the node is not dynamically allocated or is separately managed.

#### Syntax

    mxml_node_t *
    mxmlNewCustom(
        mxml_node_t * parent,
        void * data,
        void (*destroy)(void *));

#### Arguments

Name | Description
--- | ---
`parent` | Parent node or MXML_NO_PARENT
`data` | Pointer to data
`(*destroy)(void *)` | Function to destroy data

#### Returns

New node

### mxmlNewElement()

#### Description

Create a new element node. The new element node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new element node has no parent.

#### Syntax

    mxml_node_t *
    mxmlNewElement(
        mxml_node_t * parent,
        const char * name);

#### Arguments

Name | Description
--- | ---
`parent` | Parent node or MXML_NO_PARENT
`name` | Name of element

#### Returns

New node

### mxmlNewInteger()

#### Description

Create a new integer node. The new integer node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new integer node has no parent.

#### Syntax

    mxml_node_t *
    mxmlNewInteger(
        mxml_node_t * parent,
        int integer);

#### Arguments

Name | Description
--- | ---
`parent` | Parent node or MXML_NO_PARENT
`integer` | Integer value

#### Returns

New node

### mxmlNewOpaque()

#### Description

Create a new opaque string. The new opaque node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new opaque node has no parent. The opaque string must be nul-terminated and is copied into the new node.

#### Syntax

    mxml_node_t *
    mxmlNewOpaque(
        mxml_node_t * parent,
        const char * opaque);

#### Arguments

Name | Description
--- | ---
`parent` | Parent node or MXML_NO_PARENT
`opaque` | Opaque string

#### Returns

New node

### mxmlNewReal()

#### Description

Create a new real number node. The new real number node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new real number node has no parent.

#### Syntax

    mxml_node_t *
    mxmlNewReal(
        mxml_node_t * parent,
        double real);

#### Arguments

Name | Description
--- | ---
`parent` | Parent node or MXML_NO_PARENT
`real` | Real number value

#### Returns

New node

### mxmlNewText()

#### Description

Create a new text fragment node. The new text node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new text node has no parent. The whitespace parameter is used to specify whether leading whitespace is present before the node. The text string must be nul-terminated and is copied into the new node.

#### Syntax

    mxml_node_t *
    mxmlNewText(
        mxml_node_t * parent,
        int whitespace,
        const char * string);

#### Arguments

Name | Description
--- | ---
`parent` | Parent node or MXML_NO_PARENT
`whitespace` | 1 = leading whitespace, 0 = no whitespace
`string` | String

#### Returns

New node

### mxmlNewTextf()

#### Description

Create a new formatted text fragment node. The new text node is added to the end of the specified parent's child list. The constant MXML_NO_PARENT can be used to specify that the new text node has no parent. The whitespace parameter is used to specify whether leading whitespace is present before the node. The format string must be nul-terminated and is formatted into the new node.

#### Syntax

    mxml_node_t *
    mxmlNewTextf(
        mxml_node_t * parent,
        int whitespace,
        const char * format,
        ...);

#### Arguments

Name | Description
--- | ---
`parent` | Parent node or MXML_NO_PARENT
`whitespace` | 1 = leading whitespace, 0 = no whitespace
`format` | Printf-style frmat string
`...` | Additional args as needed

#### Returns

New node

### mxmlRemove()

#### Description

Remove a node from its parent. Does not free memory used by the node - use mxmlDelete() for that. This function does nothing if the node has no parent.

#### Syntax

    void
    mxmlRemove(
        mxml_node_t * node);

#### Arguments

Name | Description
--- | ---
`node` | Node to remove

#### Returns

Nothing.

### mxmlSaveAllocString()

#### Description

Save an XML node tree to an allocated string. This function returns a pointer to a string containing the textual representation of the XML node tree. The string should be freed using the free() function when you are done with it. NULL is returned if the node would produce an empty string or if the string cannot be allocated. The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

#### Syntax

    char *
    mxmlSaveAllocString(
        mxml_node_t * node,
        const char * (*cb)(mxml_node_t *node, int ws));

#### Arguments

Name | Description
--- | ---
`node` | Node to write
`(*cb)(mxml_node_t *node, int ws)` | Whitespace callback or MXML_NO_CALLBACK

#### Returns

Allocated string or NULL

### mxmlSaveFd()

#### Description

Save an XML tree to a file descriptor. The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

#### Syntax

    int
    mxmlSaveFd(
        mxml_node_t * node,
        int fd,
        const char * (*cb)(mxml_node_t *node, int ws));

#### Arguments

Name | Description
--- | ---
`node` | Node to write
`fd` | File descriptor to write to
`(*cb)(mxml_node_t *node, int ws)` | Whitespace callback or MXML_NO_CALLBACK

#### Returns

0 on success, -1 on error.

### mxmlSaveFile()

#### Description

Save an XML tree to a file. The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

#### Syntax

    int
    mxmlSaveFile(
        mxml_node_t * node,
        FILE * fp,
        const char * (*cb)(mxml_node_t *node, int ws));

#### Arguments

Name | Description
--- | ---
`node` | Node to write
`fp` | File to write to
`(*cb)(mxml_node_t *node, int ws)` | Whitespace callback or MXML_NO_CALLBACK

#### Returns

0 on success, -1 on error.

### mxmlSaveString()

#### Description

Save an XML node tree to a string. This function returns the total number of bytes that would be required for the string but only copies (bufsize - 1) characters into the specified buffer. The callback argument specifies a function that returns a whitespace string or NULL before and after each element. If MXML_NO_CALLBACK is specified, whitespace will only be added before MXML_TEXT nodes with leading whitespace and before attribute names inside opening element tags.

#### Syntax

    int
    mxmlSaveString(
        mxml_node_t * node,
        char * buffer,
        int bufsize,
        const char * (*cb)(mxml_node_t *node, int ws));

#### Arguments

Name | Description
--- | ---
`node` | Node to write
`buffer` | String buffer
`bufsize` | Size of string buffer
`(*cb)(mxml_node_t *node, int ws)` | Whitespace callback or MXML_NO_CALLBACK

#### Returns

Size of string

### mxmlSetCustom()

#### Description

Set the data and destructor of a custom data node. The node is not changed if it is not a custom node.

#### Syntax

    int
    mxmlSetCustom(
        mxml_node_t * node,
        void * data,
        void (*destroy)(void *));

#### Arguments

Name | Description
--- | ---
`node` | Node to set
`data` | New data pointer
`(*destroy)(void *)` | New destructor function

#### Returns

0 on success, -1 on failure

### mxmlSetCustomHandlers()

#### Description

Set the handling functions for custom data. The load function accepts a node pointer and a data string and must return 0 on success and non-zero on error. The save function accepts a node pointer and must return a malloc'd string on success and NULL on error.

#### Syntax

    void
    mxmlSetCustomHandlers(
        mxml_custom_load_cb_t load,
        mxml_custom_save_cb_t save);

#### Arguments

Name | Description
--- | ---
`load` | Load function
`save` | Save function

#### Returns

Nothing.

### mxmlSetElement()

#### Description

Set the name of an element node. The node is not changed if it is not an element node.

#### Syntax

    int
    mxmlSetElement(
        mxml_node_t * node,
        const char * name);

#### Arguments

Name | Description
--- | ---
`node` | Node to set
`name` | New name string

#### Returns

0 on success, -1 on failure

### mxmlSetErrorCallback()

#### Description

Set the error message callback.

#### Syntax

    void
    mxmlSetErrorCallback(
        void (*cb)(const char *));

#### Arguments

Name | Description
--- | ---
`(*cb)(const char *)` | Error callback function

#### Returns

Nothing.

### mxmlSetInteger()

#### Description

Set the value of an integer node. The node is not changed if it is not an integer node.

#### Syntax

    int
    mxmlSetInteger(
        mxml_node_t * node,
        int integer);

#### Arguments

Name | Description
--- | ---
`node` | Node to set
`integer` | Integer value

#### Returns

0 on success, -1 on failure

### mxmlSetOpaque()

#### Description

Set the value of an opaque node. The node is not changed if it is not an opaque node.

#### Syntax

    int
    mxmlSetOpaque(
        mxml_node_t * node,
        const char * opaque);

#### Arguments

Name | Description
--- | ---
`node` | Node to set
`opaque` | Opaque string

#### Returns

0 on success, -1 on failure

### mxmlSetReal()

#### Description

Set the value of a real number node. The node is not changed if it is not a real number node.

#### Syntax

    int
    mxmlSetReal(
        mxml_node_t * node,
        double real);

#### Arguments

Name | Description
--- | ---
`node` | Node to set
`real` | Real number value

#### Returns

0 on success, -1 on failure

### mxmlSetText()

#### Description

Set the value of a text node. The node is not changed if it is not a text node.

#### Syntax

    int
    mxmlSetText(
        mxml_node_t * node,
        int whitespace,
        const char * string);

#### Arguments

Name | Description
--- | ---
`node` | Node to set
`whitespace` | 1 = leading whitespace, 0 = no whitespace
`string` | String

#### Returns

0 on success, -1 on failure

### mxmlSetTextf()

#### Description

Set the value of a text node to a formatted string. The node is not changed if it is not a text node.

#### Syntax

    int
    mxmlSetTextf(
        mxml_node_t * node,
        int whitespace,
        const char * format,
        ...);

#### Arguments

Name | Description
--- | ---
`node` | Node to set
`whitespace` | 1 = leading whitespace, 0 = no whitespace
`format` | Printf-style format string
`...` | Additional arguments as needed

#### Returns

0 on success, -1 on failure

### mxmlWalkNext()

#### Description

Walk to the next logical node in the tree. The descend argument controls whether the first child is considered to be the next node. The top node argument constrains the walk to the node's children.

#### Syntax

    mxml_node_t *
    mxmlWalkNext(
        mxml_node_t * node,
        mxml_node_t * top,
        int descend);

#### Arguments

Name | Description
--- | ---
`node` | Current node
`top` | Top node
`descend` | Descend into tree - MXML_DESCEND, MXML_NO_DESCEND, or MXML_DESCEND_FIRST

#### Returns

Next node or NULL

### mxmlWalkPrev()

#### Description

Walk to the previous logical node in the tree. The descend argument controls whether the previous node's last child is considered to be the previous node. The top node argument constrains the walk to the node's children.

#### Syntax

    mxml_node_t *
    mxmlWalkPrev(
        mxml_node_t * node,
        mxml_node_t * top,
        int descend);

#### Arguments

Name | Description
--- | ---
`node` | Current node
`top` | Top node
`descend` | Descend into tree - MXML_DESCEND, MXML_NO_DESCEND, or MXML_DESCEND_FIRST

#### Returns

Previous node or NULL

## Structures

- `mxml_attr_s`
- `mxml_custom_s`
- `mxml_index_s`
- `mxml_node_s`
- `mxml_text_s`
- `mxml_value_s`

### mxml_attr_s

#### Description

An XML element attribute value.

#### Definition

    struct mxml_attr_s
    {
      char * name;
      char * value;
    };

#### Members

Name | Description
--- | ---
`name` | Attribute name
`value` | Attribute value

### mxml_custom_s

#### Description

An XML custom value.

#### Definition

    struct mxml_custom_s
    {
      void * data;
    };

#### Members

Name | Description
--- | ---
`data` | Pointer to (allocated) custom data

### mxml_index_s

#### Description

An XML node index.

#### Definition

    struct mxml_index_s
    {
      int alloc_nodes;
      char * attr;
      int cur_node;
      mxml_node_t ** nodes;
      int num_nodes;
    };

#### Members

Name | Description
--- | ---
`alloc_nodes` | Allocated nodes in index
`attr` | Attribute used for indexing or NULL
`cur_node` | Current node
`nodes` | Node array
`num_nodes` | Number of nodes in index

### mxml_node_s

#### Description

An XML node.

#### Definition

    struct mxml_node_s
    {
      struct mxml_node_s * child;
      struct mxml_node_s * last_child;
      struct mxml_node_s * next;
      struct mxml_node_s * parent;
      struct mxml_node_s * prev;
      mxml_type_t type;
      mxml_value_t value;
    };

#### Members

Name | Description
--- | ---
`child` | First child node
`last_child` | Last child node
`next` | Next node under same parent
`parent` | Parent node
`prev` | Previous node under same parent
`type` | Node type
`value` | Node value

### mxml_text_s

#### Description

An XML text value.

#### Definition

    struct mxml_text_s
    {
      char * string;
      int whitespace;
    };

#### Members

Name | Description
--- | ---
`string` | Fragment string
`whitespace` | Leading whitespace?

### mxml_value_s

#### Description

An XML element value.

#### Definition

    struct mxml_value_s
    {
      mxml_attr_t * attrs;
      char * name;
      int num_attrs;
    };

#### Members

Name | Description
--- | ---
`attrs` | Attributes
`name` | Name of element
`num_attrs` | Number of attributes

## Types

- `mxml_attr_t`
- `mxml_custom_t`
- `mxml_element_t`
- `mxml_index_t`
- `mxml_node_t`
- `mxml_text_t`
- `mxml_type_t`
- `mxml_value_t`

### mxml_attr_t

#### Description

An XML element attribute value.

#### Definition

    typedef struct mxml_attr_s mxml_attr_t;

### mxml_custom_t

#### Description

An XML custom value.

#### Definition

    typedef struct mxml_custom_s mxml_custom_t;

### mxml_element_t

#### Description

An XML element value.

#### Definition

    typedef struct mxml_value_s mxml_element_t;

### mxml_index_t

#### Description

An XML node index.

#### Definition

    typedef struct mxml_index_s mxml_index_t;

### mxml_node_t

#### Description

An XML node.

#### Definition

    typedef struct mxml_node_s mxml_node_t;

### mxml_text_t

#### Description

An XML text value.

#### Definition

    typedef struct mxml_text_s mxml_text_t;

### mxml_type_t

#### Description

The XML node type.

#### Definition

    typedef enum mxml_type_e mxml_type_t;

### mxml_value_t

#### Description

An XML node value.

#### Definition

    typedef union mxml_value_u mxml_value_t;

## Unions

- `mxml_value_u`

### mxml_value_u

#### Description

An XML node value.

#### Definition

    union mxml_value_u
    {
      mxml_custom_t custom;
      mxml_element_t element;
      int integer;
      char * opaque;
      double real;
      mxml_text_t text;
    };

#### Members

Name | Description
--- | ---
`custom` | Custom data
`element` | Element
`integer` | Integer number
`opaque` | Opaque string
`real` | Real number
`text` | Text fragment