getopt_long unrecognized option

[ShereModulus]

Hi, I'm trying to use the getopt_long function to handle parameters to my C program, in Linux. Here is the relevant code:

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <getopt.h>

#define ECB_MODE 1000

int main(int argc, char* argv[])
{
        int mode;
        struct option long_opts[2] = {
        {"ecb", no_argument, &mode, ECB_MODE},
        {0, 0, 0, 0}
    };

    while (1)
    {
        ch = getopt_long(argc, argv, "dek:i:o:", long_opts, NULL);

        if (ch == -1)
        {
            break;
        }

        switch(ch)
        {
            case 'd':
            {
                encrypt = 0;
                break;
            }
            case 'e':
            {
                encrypt = 1;
                break;
            }
            case 'i':
            {
                infilename = optarg;
                break;
            }
            case 'o':
            {
                outfilename = optarg;
                break;
            }
            case 'k':
            {
                keyfilename = optarg;
                break;
            }
            case 0:
            {
                printf("ECB option\n");
                break;
            }
            default:
            {
                printf("Invalid arguments\n");
                return 0;
            }
        }
    }
    return 0;
}

All of the short options work, but if I call the program with "--ecb" getopt_long returns '?' citing "ambiguous option". In my understanding, it should return 0 and store the value of the macro in the int variable I thoughtfully provided for it in the long_opts struct. My question is, why/how is "--ecb" ambiguous, and how can I make it unambiguous?

[ShereModulus]

Never mind. I've been staring at this thing for about two hours, and of course five minutes after I post this for the entire world to see I realize that I had been writing --enc on the command line instead of --ecb. What a shipdit. It works now, though.

I apologize!