Windows平台实现awk extension模块

1. 首先需要下载编译

下载mbuilov/gawk-windows，按照说明编译成功。

https://github.com/mbuilov/gawk-windows

步骤：

1. 下载依赖
   https://github.com/mbuilov/mscrtx.git
   https://github.com/mbuilov/libutf16.git
   https://github.com/mbuilov/unicode_ctype.git

2. 打开”x64 Native Tools Command Prompt for VS 20XX"

set "MSCRTX=\path\to\mscrtx-master"
set "LIBUTF16=\path\to\libutf16-master"
set "UNICODE_CTYPE=\path\to\unicode_ctype-master"

3. cd \path\to\gawk-windows-new-master
4. build.bat all

这里有一些自带的extension可以提供参考。

2. 实现myawkext.c

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdio.h>
#include <inttypes.h>

#include "gawkapi.h"

GAWK_PLUGIN_GPL_COMPATIBLE
GAWK_PLUGIN("my awk extension: version 1.0");


static awk_value_t *
do_mystrlen(int nargs, awk_value_t *result, struct awk_ext_func *unused)
{
        int ret = 0;
        awk_value_t file_param, array_param;
        const char *name;

        if (! get_argument(0, AWK_STRING, & file_param)) {
                return make_number(-1, result);
        }

        name = file_param.str_value.str;
        ret = strlen(name);

        return make_number(ret, result);
}

static awk_bool_t
init_myawkext(void)
{
        int errors = 0;
        return (awk_bool_t) (errors == 0);
}

static awk_ext_func_t myawkext_funcs[] = {
        { "mystrlen",   do_mystrlen, 3, 1, awk_false, NULL },
};


dl_load_func(init_myawkext, myawkext_funcs, myawkext, "")

定义了myawkext.c文件，提供一个函数："mystrlen"返回字符串的长度。
注意这里用到的两个头文件，"config.h"和"gawkapi.h"都是gawk生成的。

3. 编译

rm -f myawkext.obj
rm -f myawkext.dll
rm -f myawkext.exp
rm -f myawkext.lib

set GAWKWINHOME=c:/path/to/gawk-windows-new-master

cl.exe /LD /DHAVE_CONFIG_H -I%GAWKWINHOME% -I%GAWKWINHOME%/pc myawkext.c

REM Or
REM cl.exe /c /DHAVE_CONFIG_H -I%GAWKWINHOME% -I%GAWKWINHOME%/pc /Fomyawkext.obj myawkext.c
REM link.exe /DLL /OUT:myawkext.dll myawkext.obj

4. 运行

> cat test.awk
@load "myawkext"
BEGIN {
   printf "len=%d\n", mystrlen("1234567")
}


> awk -f test.awk
7