是否可以使用 getopt_long 来解析类似于 C 程序中的命令行参数的字符串数组？

Question

我知道应该使用 getopt 来解析命令行参数，而不是字符串。

但是，我感到困惑的是，如果我向它传递一个字符串数组，"looks like" argv 变量，getopt_long 似乎有效，但 只有第一个我称之为的时间。对于第二次和所有后续时间，我称之为它忽略任何参数和 returns 默认参数。

我这样做的原因是我正在将一个应用程序转换为一个 "interactive" 版本的命令行参数，它要求用户提供一些参数，然后根据这些参数执行一些操作争论，然后要求更多的争论等等。

以下代码是重现错误的最小示例

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>

struct input_parameters{
    char * d; // data set
};

int solver_help(int argc, char* const argv[], struct input_parameters * p)
{
  int c;

  p->d = "default name";

  while (1)
  {
      static struct option long_options[] =
      {
          {"data",  required_argument,     0, 'd'},
          {0, 0, 0, 0}
      };
      /* getopt_long stores the option index here. */
      int option_index = 0;

      c = getopt_long (argc, argv, "d:",
                       long_options, &option_index);

      /* Detect the end of the options. */
      if (c == -1)
        break;

      switch (c)
      {
          case 'd': p->d = optarg;
              break;
          default:
              printf("wrong option specification\n");
              exit(-1);
      }
  }

  return 0 ;


}    


int main () {

    int argc_first = 3;
    char * const argv_first[] = { "getopt_test", "--data", "first" };
    struct input_parameters first_input;
    solver_help(argc_first, argv_first, &first_input);

    printf("I think the data is: %s\n", first_input.d);

    int argc_second = 3;
    char * const argv_second[] = { "getopt_test","--data", "second" };
    struct input_parameters second_input;
    solver_help(argc_second, argv_second, &second_input);

    printf("I think the data is: %s\n", second_input.d);

    return 0;
}

这段代码的输出是

I think the data is: first
I think the data is: default name

Answer 1

来自 getopt 的手册页：

In order to use getopt() to evaluate multiple sets of arguments, or to evaluate a single set of arguments multiple times, the variable optreset must be set to 1 before the second and each additional set of calls to getopt(), and the variable optind must be reinitialized.

稍微修改您的代码即可获得所需的结果：

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>

struct input_parameters {
    char * d; // data set
};

int solver_help(int argc, char* const argv[], struct input_parameters * p)
{
    p->d = "default name";

    static struct option long_options[] =
    {
        {"data",  required_argument,     0, 'd'},
        {0, 0, 0, 0}
    };

    int option_index = 0;

    optreset = 1;     /*  ADD THIS  */
    optind = 1;       /*  ADD THIS  */

    int c = getopt_long(argc, argv, "d:",
                        long_options, &option_index);

    switch ( c )
    {
        case -1:
            break;

        case 'd':
            p->d = optarg;
            break;

        default:
            printf("in default case...\n");
            printf("wrong option specification\n");
            exit(EXIT_FAILURE);
    }

    return 0;
}    

int main(void) {

    int argc_first = 3;
    char * const argv_first[] = { "getopt_test", "--data", "first" };
    struct input_parameters first_input;
    solver_help(argc_first, argv_first, &first_input);

    printf("I think the data is: %s\n", first_input.d);

    int argc_second = 3;
    char * const argv_second[] = { "getopt_test","--data", "second" };
    struct input_parameters second_input;
    solver_help(argc_second, argv_second, &second_input);

    printf("I think the data is: %s\n", second_input.d);

    return 0;
}

输出：

paul@horus:~/src/sandbox$ ./go
I think the data is: first
I think the data is: second
paul@horus:~/src/sandbox$

是否可以使用 getopt_long 来解析类似于 C 程序中的命令行参数的字符串数组？

is it possible to use getopt_long to parse arrays of strings similar to command line arguments in a C program?

c

getopt

getopt-long