linux编程mxml安装与使用

linux编程mxml

解压

 tar -xf mxml-2.10.tar 

安装

BUILDING Mini-XML

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

        ./configure

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

        ./configure --prefix=/foo

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

        ./configure --help

    Once you have configured the software, type "make" to do the build and run
    the test program to verify that things are working, as follows:

        make

    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.  Note: The static library on Windows is NOT thread-safe.

可以看出，与一般安装一样。
先./configure。

$ ./configure
checking for gcc... gcc
checking whether the C compiler works... yes
checking for C compiler default output file name... a.out
checking for suffix of executables... 
checking whether we are cross compiling... no
checking for suffix of object files... o
...
checking for shared library support... yes
configure: creating ./config.status
config.status: creating Makefile
config.status: creating mxml.list
config.status: creating mxml.pc
config.status: creating config.h
$

再执行make，最后执行sudo make install，安装成功。
默认就是安装在/usr/local的，如果安装在其它位置，要在/etc/ld.so.conf.d/libc.conf文件配置上路径。

# libc default configuration
/usr/local/lib

注意 ，生成Makefile时，也可以关闭线程支持./configure --enable-threads=no。

使用

使用的话，加上#include <mxml.h>头文件就行。

#include <stdio.h>
#include <mxml.h>

int main(int argc, const char* argv[])
{
    // 创建xml文件头节点
    mxml_node_t *xml = mxmlNewXML("1.0");

    // 创建xml根节点 - china
    mxml_node_t* china = mxmlNewElement(xml, "China");


    // 创建城市节点
    mxml_node_t* city = mxmlNewElement(china, "City");
    // 添加子节点
    // name
    mxml_node_t* name = mxmlNewElement(city, "Name");
    // 设置标签值
    mxmlNewText(name, 0, "北京");
    mxmlElementSetAttr(name, "isbig", "true");
    // 面积
    mxml_node_t* area = mxmlNewElement(city, "Area");
    mxmlNewText(area, 0, "1.641万平方千米");
    // 人口
    mxml_node_t* popu = mxmlNewElement(city, "Population");
    mxmlNewText(popu, 0, "2200万");

    // 第二个城市节点
    city = mxmlNewElement(china, "City");
    // name
    name = mxmlNewElement(city, "Name");
    mxmlNewText(name, 0, "石家庄");
    mxmlElementSetAttr(name, "isbig", "false");
    area = mxmlNewElement(city, "Area");
    mxmlNewText(area, 0, "15848平方千米");
    popu = mxmlNewElement(city, "Population");
    mxmlNewText(popu, 0, "107万");

    // 将xml内容保存到磁盘
    FILE* fp = fopen("china.xml", "w");
    mxmlSaveFile(xml, fp, MXML_NO_CALLBACK);
    fclose(fp);
    mxmlDelete(xml);
    
    return 0;
}

运行

$ gcc create_xml.c -o create
/usr/bin/ld: /tmp/ccMJhREG.o: in function `main':
create_xml.c:(.text+0x15): undefined reference to `mxmlNewXML'
/usr/bin/ld: create_xml.c:(.text+0x2a): undefined reference to `mxmlNewElement'
/usr/bin/ld: create_xml.c:(.text+0x3f): undefined reference to `mxmlNewElement'
/usr/bin/ld: create_xml.c:(.text+0x54): undefined reference to `mxmlNewElement'
/usr/bin/ld: create_xml.c:(.text+0x6e): undefined reference to `mxmlNewText'
/usr/bin/ld: create_xml.c:(.text+0x84): undefined reference to `mxmlElementSetAttr'
/usr/bin/ld: create_xml.c:(.text+0x95): undefined reference to `mxmlNewElement'
/usr/bin/ld: create_xml.c:(.text+0xaf): undefined reference to `mxmlNewText'

运行时发现报错了，库没引用对，gcc create_xml.c -lmxml -o create

$ gcc create_xml.c -lmxml -o create
/usr/bin/ld: //usr/local/lib/libmxml.so: undefined reference to `pthread_getspecific'
/usr/bin/ld: //usr/local/lib/libmxml.so: undefined reference to `pthread_key_create'
/usr/bin/ld: //usr/local/lib/libmxml.so: undefined reference to `pthread_once'
/usr/bin/ld: //usr/local/lib/libmxml.so: undefined reference to `pthread_setspecific'
/usr/bin/ld: //usr/local/lib/libmxml.so: undefined reference to `pthread_key_delete'
collect2: error: ld returned 1 exit status 

缺线程库 ，加上-lpthread。所以完整的命令是gcc create_xml.c -lmxml -lpthread -o create编译成功。
如果报找不到库，更新一下缓存sudo ldconfig。

$ ./create
./create: error while loading shared libraries: libmxml.so.1: cannot open shared object file: No such file or directory
$ sudo ldconfig
$ ./create
$ ls
china.xml  create  create_xml.c 

查看china.xml

<?xml version="1.0" encoding="utf-8"?>
<China>
	<City>
		<Name isbig="true">北京</Name>
		<Area>1.641万平方千米</Area>
		<Population>2200万</Population>
	</City>
	<City>
		<Name isbig="false">石家庄</Name>
		<Area>15848平方千米</Area>
		<Population>107万</Population>
	</City>
</China>

解析

#include <stdio.h>
#include <mxml.h>

int main(int argc, const char* argv[])
{
    // 从磁盘加载xml文件
    FILE* fp = fopen("china.xml", "r");
    if(fp == NULL)
    {
        printf("fopen error\n");
        return 0;
    }
    // root 节点指向xml文件头
    mxml_node_t* root = mxmlLoadFile(NULL, fp, MXML_NO_CALLBACK);

    // 遍历 - 取出各个节点的值
    // 找到第一个城市节点
    mxml_node_t* city = mxmlFindElement(root, root, "City", NULL, NULL, MXML_DESCEND);
    if(city == NULL)
    {
        printf("xml node not found\n");
        return 0;
    }
    while( city  )
    {
        printf("==================\n");
        // 向下走一个节点
        mxml_node_t* node = mxmlWalkNext(city, root, MXML_DESCEND_FIRST);
        printf("city:   \n");
        printf("    name = %s\n", mxmlGetText(node, NULL));
        // 
        node = mxmlWalkNext(node, root, MXML_NO_DESCEND);
        printf("    area = %s\n", mxmlGetText(node, NULL));
        //
        node = mxmlWalkNext(node, root, MXML_NO_DESCEND);
        printf("    population = %s\n", mxmlGetText(node, NULL));
        // 搜索下一个城市节点
        city = mxmlFindElement(city, root, "City", NULL, NULL, MXML_DESCEND);
    }

    fclose(fp);
    mxmlDelete(root);

    return 0;
}

其它

xml简单介绍及libmxml编程
解决error while loading shared libraries: libXXX.so.X: cannot open shared object file: No such file