linux编程mxml安装与使用

Dear 丶 2022-12-02 15:06 498阅读 0赞

# 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][xml_libmxml]  
[解决error while loading shared libraries: libXXX.so.X: cannot open shared object file: No such file][error while loading shared libraries_ libXXX.so.X_ cannot open shared object file_ No such file]

[xml_libmxml]: https://www.cnblogs.com/liunianshiwei/p/6086577.html
[error while loading shared libraries_ libXXX.so.X_ cannot open shared object file_ No such file]: https://blog.csdn.net/deeplan_1994/article/details/83927832