Argument-parsing helpers for C/Unix

Question

I know of the following:

• The venerable getopt(3)
• The extended getopt_long
• glibc\'s argp parser for Unix-style argum

Answer 1

I'm not too fond of getopt either (although it's pretty standard). One solution I've made is the function argopt(). It's C compatible, can be used to test whether flags are set as well as reading options with values. It only supports short options (e.g. -h) although writing a similar function for long options (e.g. --help) shouldn't be too difficult. See example:

int main(int argc, char **argv){

    if(argopt(argc, argv, 'p')) printf("-p is set\n");
    if(argopt(argc, argv, 'q')) printf("-q is set\n");

    const char *f = argopt(argc, argv, 'f');
    if(f) printf("-f is %s\n",f);

    return 0;
}

Example from command line:

$./main -f input.txt -rq
-q is set
-f is input.txt

Disclaimer: I made this function for fun, intending for it to be short, C-compatible, easy to use, and have no dependencies. Here it is:

const char* argopt(int argc, const char *const *argv, char key){

    for(int i=1; i<argc; i++){
        const char *c = argv[i];
        if(*c!='-') continue;
        while(*++c) if(*c==key) return argv[(i+1)%argc];
    }

    return 0;
}