Getopt() Accepting Other Option as Argument in C

Question

So I searched high and low for an answer to this question and all I could find was someone who poorly asked the same question 2 years ago and was never really answered ( option followed by a option in getopt [where the earlier option was expecting a value] ).

Currently, I am writing a program that is supposed to accept command line options and arguments. The command is supposed to create and manipulate an archive file supplied through the command line. I am using getopt() . The usage for the command is oscar [options] [archive-file] [member files] however some of the options do not require arguments. Such as a '-v' flag which stands for verbose and simply causes other actions in the file to spit out more print statements than the default.

Here is my code for using getopt():

 //declaring some variables to be used by getopt
 18     extern char *optarg;    //pointer to options that require an argument
 19     extern int optind;      //index into main()'s argument list (argv[])
 20
 21     int getOptReturn = 0;   //int that stores getopt's return (used to check if it is done parsing)
 22     int error = 0;          //flag for '?' case if getopt doesn't receive proper input
 23
 24     //flags for all the options
 25     int a_flag, A_flag, v_flag, C_flag, d_flag, e_flag, h_flag,
 26     m_flag, o_flag, t_flag, T_flag, E_flag, V_flag, u_flag = 0;
 27
 28     int i;                  //for loops index
 29
 30     char *aname;
 31
 32     //while parsing options
 33     while((getOptReturn = getopt(argc, argv, "a:A:Cd:e:E:hm:otTu:vV")) != -1)
 34     {
 35         //debugging
 36         printf("optind: %d, option: %c, optarg: %s \n", optind, argv[optind], optarg);
 37         printf("%d\n", argc);
 38
 39         //switch options and set appropriate flags
 40         switch(getOptReturn)
 41         {
 42             case 'a':
 43                 printf("-a option received\n");
 44                 //turn add flag on
 45                 a_flag = 1;
 46                 aname = optarg;
 47                 printf("argument supplied to -a: %s \n", aname);
 48                 break;
 49             case 'A':
 50                 printf("-A option received\n");
 51                 //turn add all flag on
 52                 A_flag = 1;
 53                 aname = optarg;
 54                 printf("argument supplied to -A: %s \n", aname);
 55                 break;
 56             case 'v':
 57                 printf("-v option received\n");
 58                 //turn verbose flag on
 59                 v_flag = 1;
 60                 printf("verbose flag turned on!\n");
 61                 break;

Now the problem that I'm facing is that the order I'm passing the option characters in currently matters when it is not supposed to.

For example:

If i call the function with ./oscar -va archive the code functions properly and v causes the v flag to be turned on, and a is processed with archive as the argument because I required a to have an argument inside of getopt() .

However, if I call the function with ./oscar -av archive the code reads in a and assigns v as its required argument instead of reading v as an option and using archive as the argument for a .

Is there any way I can tell getopt() to skip over other option values in argv[] so that I can call the function from the command line with all sorts of combinations and not worry about order such as:

./oscar -avo archive file1 file2 file3...

./oscar -a A v archive file1 file2...

Answer 1

According to user nm 's comment, this is just how command line arguments are supposed to behave as specified by the POSIX guidelines.

From his comment:

"One or more options without option-arguments, followed by at most one option that takes an option-argument, should be accepted when grouped behind one '-' delimiter."

If you desire the functionality I was looking for, you need to use the external variable that getopt supplies you with: optind paired with argc and argv[] to manually handle more options that require arguments.

Thanks for reading.