24.6 getopt()、getopt_long()、getopt_long_only()是何用法

Q: 能给一个getopt()的例子吗

A: 小四 <scz@nsfocus.com> 1999-04-05 17:02

--------------------------------------------------------------------------
/*
 * For x86/Linux
 * gcc -Wall -pipe -O3 -s -o getopt_test getopt_test.c
 */

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <unistd.h>

#define VERSION "1.00 1999-04-05 17:02"

static void usage ( char *arg )
{
    fprintf
    (
        stderr,
        "Usage: %s [-h] [-v] [-i intvar] [-s strvar]\n",
        arg
    );
    exit( EXIT_FAILURE );
}  /* end of usage */

int main ( int argc, char * argv[] )
{
    int             ret     = EXIT_FAILURE;
    int             c;
    unsigned int    intvar  = 0;
    char           *strvar  = NULL;

    if ( 1 == argc )
    {
        usage( argv[0] );
    }
    /*
     * don't want getopt() writing to stderr
     */
    opterr  = 0;
    /*
     * getopt()第三形参最前面如果有冒号，就不会出现illegal option错误信息。
     * 不过，如果指定了"opterr = 0"，有无这个前导冒号都无所谓了。
     */
    while ( EOF != ( c = getopt( argc, argv, ":hi:s:v" ) ) )
    {
        switch ( c )
        {
        case 'i':
            intvar  = ( unsigned int )strtoul( optarg, NULL, 0 );
            break;
        case 's':
            strvar  = optarg;
            break;
        case 'v':
            printf( "%s ver "VERSION"\n", argv[0] );
            return( EXIT_SUCCESS );
        case 'h':
        case '?':
        default :
            usage( argv[0] );
            break;
        }  /* end of switch */
    }  /* end of while */
    argc   -= optind;
    argv   += optind;
    printf
    (
        "intvar  = %u\n"
        "strvar  = %s\n",
        intvar,
        NULL == strvar ? "(null)" : strvar
    );
    ret     = EXIT_SUCCESS;
    return( ret );
}  /* end of main */

#if 0

$ ./getopt_test -h
Usage: ./getopt_test [-h] [-v] [-i intvar] [-s strvar]
$ ./getopt_test -i 1314 -s scz
intvar  = 1314
strvar  = scz
$ ./getopt_test -v
./getopt_test ver 1.00 1999-04-05 17:02

#endif
--------------------------------------------------------------------------

Q: 现在会用getopt()了，但如何支持"--parami intvar --params strvar"呢

A: 小四 <scz@nsfocus.com> 2001-12-17 15:30

这需要用到getopt_long()，但这不是一个具有良好可移植性的函数。

--------------------------------------------------------------------------
/*
 * For x86/Linux
 * gcc -Wall -pipe -O3 -s -o getopt_long_test getopt_long_test.c
 */

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <unistd.h>
/*
 * 为了使用getopt_long()，必须有如下两行内容
 */
#define _GNU_SOURCE
#include <getopt.h>

#define VERSION         "1.00 2001-12-17 15:30"
/*
 * 不要与短选项所用的字符相同！
 */
#define LONGOPTIONCHAR  '*'

static void usage ( char *arg )
{
    fprintf
    (
        stderr,
        "Usage: %s [-h] [--ver] [--parami intvar] [-params strvar]\n",
        arg
    );
    exit( EXIT_FAILURE );
}  /* end of usage */

int main ( int argc, char * argv[] )
{
    int             ret             = EXIT_FAILURE;
    int             c;
    unsigned int    intvar          = 0;
    char           *strvar          = NULL;
    struct option   longOption[]    =
    {
        { "ver",    0,  NULL,   LONGOPTIONCHAR },
        { "parami", 1,  NULL,   LONGOPTIONCHAR },
        { "params", 1,  NULL,   LONGOPTIONCHAR },
        { NULL,     0,  NULL,   0              }
    };
    int             longOptionIndex = 0;

    if ( 1 == argc )
    {
        usage( argv[0] );
    }
    /*
     * don't want getopt() writing to stderr
     */
    opterr  = 0;
    while ( EOF != ( c = getopt_long( argc, argv, ":h", longOption, &longOptionIndex ) ) )
    {
        switch ( c )
        {
        case LONGOPTIONCHAR:
            if ( optarg )
            {
                switch ( longOptionIndex )
                {
                case 1:
                    intvar  = ( unsigned int )strtoul( optarg, NULL, 0 );
                    break;
                case 2:
                    strvar  = optarg;
                    break;
                default:
                    break;
                }  /* end of switch */
            }
            else
            {
                switch ( longOptionIndex )
                {
                /*
                 * longOption[]的下标
                 */
                case 0:
                    printf( "%s ver "VERSION"\n", argv[0] );
                    return( EXIT_SUCCESS );
                default:
                    break;
                }  /* end of switch */
            }
            break;
        case 'h':
        case '?':
        default :
            usage( argv[0] );
            break;
        }  /* end of switch */
    }  /* end of while */
    argc   -= optind;
    argv   += optind;
    printf
    (
        "intvar  = %u\n"
        "strvar  = %s\n",
        intvar,
        NULL == strvar ? "(null)" : strvar
    );
    ret     = EXIT_SUCCESS;
    return( ret );
}  /* end of main */

#if 0

$ ./getopt_long_test -h
Usage: ./getopt_long_test [-h] [--ver] [--parami intvar] [-params strvar]
$ ./getopt_long_test --parami 1314 --params scz
intvar  = 1314
strvar  = scz
$ ./getopt_long_test --ver
./getopt_long_test ver 1.00 2001-12-17 15:30

#endif
--------------------------------------------------------------------------

Q: 那getopt_long_only()与getopt_long()的区别是什么

A: 小四 <scz@nsfocus.com> 2005-05-09 10:48

getopt_long_only()的行为与getopt_long()非常类似，但不限于用'--'引入长选项，
'-'亦可引入长选项。当'-'引入的选项不匹配任何长选项时，继续进行短选项匹配。

再次提醒，getopt_long_only()与getopt_long()一样，不具有良好可移植性。

--------------------------------------------------------------------------
/*
 * For x86/Linux
 * gcc -Wall -pipe -O3 -s -o getopt_long_only_test getopt_long_only_test.c
 */

#include <stdio.h>
#include <stdlib.h>
#include <strings.h>
#include <string.h>
#include <unistd.h>
/*
 * 为了使用getopt_long_only()，必须有如下两行内容
 */
#define _GNU_SOURCE
#include <getopt.h>

#define VERSION         "1.00 2005-05-09 10:48"
/*
 * 不要与短选项所用的字符相同！这次用空格符，更可靠些。
 */
#define LONGOPTIONCHAR  ' '

static void usage ( char *arg )
{
    fprintf
    (
        stderr,
        "Usage: %s [-h] [--v] [-i intvar] [--s strvar]\n",
        arg
    );
    exit( EXIT_FAILURE );
}  /* end of usage */

int main ( int argc, char * argv[] )
{
    int             ret             = EXIT_FAILURE;
    int             c;
    unsigned int    intvar          = 0;
    char           *strvar          = NULL;
    struct option   longOption[]    =
    {
        { "v",      0,  NULL,   LONGOPTIONCHAR },
        { "s",      1,  NULL,   LONGOPTIONCHAR },
        { NULL,     0,  NULL,   0              }
    };
    int             longOptionIndex = 0;

    if ( 1 == argc )
    {
        usage( argv[0] );
    }
    /*
     * don't want getopt() writing to stderr
     */
    opterr  = 0;
    while ( EOF != ( c = getopt_long_only( argc, argv, ":hi:", longOption, &longOptionIndex ) ) )
    {
        switch ( c )
        {
        case LONGOPTIONCHAR:
            if ( optarg )
            {
                switch ( longOptionIndex )
                {
                case 1:
                    strvar  = optarg;
                    break;
                default:
                    break;
                }  /* end of switch */
            }
            else
            {
                switch ( longOptionIndex )
                {
                /*
                 * longOption[]的下标
                 */
                case 0:
                    printf( "%s ver "VERSION"\n", argv[0] );
                    return( EXIT_SUCCESS );
                default:
                    break;
                }  /* end of switch */
            }
            break;
        case 'i':
            intvar  = ( unsigned int )strtoul( optarg, NULL, 0 );
            break;
        case 'h':
        case '?':
        default :
            usage( argv[0] );
            break;
        }  /* end of switch */
    }  /* end of while */
    argc   -= optind;
    argv   += optind;
    printf
    (
        "intvar  = %u\n"
        "strvar  = %s\n",
        intvar,
        NULL == strvar ? "(null)" : strvar
    );
    ret     = EXIT_SUCCESS;
    return( ret );
}  /* end of main */

#if 0

$ ./getopt_long_only_test -h
Usage: ./getopt_long_only_test [-h] [--v] [-i intvar] [--s strvar]
$ ./getopt_long_only_test --v
./getopt_long_only_test ver 1.00 2005-05-09 10:48
$ ./getopt_long_only_test -v
./getopt_long_only_test ver 1.00 2005-05-09 10:48
$ ./getopt_long_only_test -i 1314 -s scz
intvar  = 1314
strvar  = scz

#endif
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