multiple values for optarg

Question

I want to be able to get 2 values for -a arg like: -a min max

I have the following code:

while((opt = getopt(argc,argv,"a:c:k:rv")) != -1)
{
    switch (opt)
    {
         case 'a':
                min = atoi(optarg);
                fprintf( stderr,"value1: %s\n", optarg);
                optind--;
                for( ;optind < argc && *argv[optind] != '-'; optind++)
                {
                    optind++;
                    fprintf( stderr,"value2: %s\n", optarg);
                    max = atoi(optarg);
                }
            break;
          //other cases
     }
}

How can I get multiple values for a single argument?

Answer 1

The easiest way to accept two parameters of an option is to join them with a non-blank character like ':':

myprogram -a min:max other-options

This way getopt thinks of it as of a single parameter. When you handle it you need to separate it in two yourself. If both halves are numbers, then this should work:

if (sscanf(optarg, "%d:%d", &min, &max) != 2)
  /* report an error */