optim

Immediate-mode command line option parsing for C.

Features

• Immediate-mode: declare, read, and validate locally
• Auto-generated usage message (--help)
• Options parsing can be split over multiple functions
• Supports long and short options, with and without arguments
• Supports positional arguments and --
• Supports repeated arguments
• Plays nice with help2man
• Doesn't rely on macros or preprocessor trickery
• Opinionated only when it makes things simpler

Example Generated Usage

See test/main.c

Usage: optim_test [-a] [-b] <path>

My test optim program

Options:
  -h, --help                  Print this help message
  -v, --verbose               Increase verbosity

Section Two:
  -a, --alpha=ARG             Alpha parameter. This usage has a lot to say, so
                                the usage spans over multiple lines
                                Newlines are also handled fine
  -b, --beta                  Beta flag
  -c                          C flag without longform
      --delta=diff            Delta parameter without short form
  -e exarg                    Extra option with an arg but no longopt

Supported Formats

Each line shows options that are parsed equivalently by optim.

• -v, --verbose
• -vvv, -v -v -v, --verbose -vv
• -a ARG, --alpha ARG, --alpha=ARG
• -va ARG, -v -a ARG, --verbose --alpha ARG

Unsupported Formats

The following examples are not parsed correctly by optim.

• -aARG
• -a=ARG
• -beta
• --alpha -ARG, use --alpha=-ARG if your argument could begin with a -

Also, optim does not currently support:

• Optional arguments (--alpha[=ARG])
• Suboptions (-o,rw)
• Subcommands (git show)

Example

int main(int argc, char ** argv) {
    optim_t * o = optim_start(argc, argv, "%s [-a] [-b|-c] <path>");
    if (o == NULL) exit(EXIT_FAILURE);

    optim_usage(o, "My test optim program\n");
    optim_version(o, "optim_test Version 1.0\nAuthor: Zach Banks\n");

    optim_flag(o, 'v', "verbose", "Increase verbosity");
    int verbosity = optim_get_count(o);

    optim_usage(o, "\nSection Two:\n");

    optim_arg(o, 'a', "alpha", NULL, "Alpha parameter");
    long alpha = optim_get_long(o, 0);
    
    optim_flag(o, 'b', "beta", "Beta flag");
    bool beta = optim_get_count(o) > 0;

    optim_flag(o, 'c', NULL, "C flag without longform");
    bool cflag = optim_get_count(o) > 0;

    if (cflag && beta)
        optim_error("cannot specify both -b and -c flags");

    optim_positionals(o);
    char * path = optim_get_string(o, NULL);
    if (path == NULL)
        optim_error(o, "must specify path");

    int rc = optim_finish(&o);
    if (rc < 0) exit(EXIT_FAILURE);

    // ...
}

About

optim is licensed under the MIT license. Copyright (c) 2017 Zach Banks.