# argparse [![Build Status](https://travis-ci.org/cofyc/argparse.png)](https://travis-ci.org/cofyc/argparse)

argparse - A command line arguments parsing library in C (compatible with C++).

## Description

This module is inspired by parse-options.c (git) and python's argparse
module.

Arguments parsing is common task in cli program, but traditional `getopt`
libraries are not easy to use. This library provides high-level arguments
parsing solutions.

The program defines what arguments it requires, and `argparse` will figure
out how to parse those out of `argc` and `argv`, it also automatically
generates help and usage messages and issues errors when users give the
program invalid arguments.

## Features

 - handles both optional and positional arguments
 - produces highly informative usage messages
 - issues errors when given invalid arguments

There are basically three types of options:

 - boolean options
 - options with mandatory argument
 - options with optional argument

There are basically two forms of options:

 - short option consist of one dash (`-`) and one alphanumeric character.
 - long option begin with two dashes (`--`) and some alphanumeric characters.

Short options may be bundled, e.g. `-a -b` can be specified as `-ab`.

Options are case-sensitive.

Options and non-option arguments can clearly be separated using the `--` option.

## Examples

```c
#include "argparse.h"

static const char *const usage[] = {
    "test_argparse [options] [[--] args]",
    "test_argparse [options]",
    NULL,
};

#define PERM_READ  (1<<0)
#define PERM_WRITE (1<<1)
#define PERM_EXEC  (1<<2)

int
main(int argc, const char **argv)
{
    int force = 0;
    int test = 0;
    int num = 0;
    const char *path = NULL;
    int perms = 0;
    struct argparse_option options[] = {
        OPT_HELP(),
        OPT_GROUP("Basic options"),
        OPT_BOOLEAN('f', "force", &force, "force to do"),
        OPT_BOOLEAN('t', "test", &test, "test only"),
        OPT_STRING('p', "path", &path, "path to read"),
        OPT_INTEGER('n', "num", &num, "selected num"),
        OPT_GROUP("Bits options"),
        OPT_BIT(0, "read", &perms, "read perm", NULL, PERM_READ, OPT_NONEG),
        OPT_BIT(0, "write", &perms, "write perm", NULL, PERM_WRITE),
        OPT_BIT(0, "exec", &perms, "exec perm", NULL, PERM_EXEC),
        OPT_END(),
    };

    struct argparse argparse;
    argparse_init(&argparse, options, usage, 0);
    argparse_describe(&argparse, "\nA brief description of what the program does and how it works.", "\nAdditional description of the program after the description of the arguments.");
    argc = argparse_parse(&argparse, argc, argv);
    if (force != 0)
        printf("force: %d\n", force);
    if (test != 0)
        printf("test: %d\n", test);
    if (path != NULL)
        printf("path: %s\n", path);
    if (num != 0)
        printf("num: %d\n", num);
    if (argc != 0) {
        printf("argc: %d\n", argc);
        int i;
        for (i = 0; i < argc; i++) {
            printf("argv[%d]: %s\n", i, *(argv + i));
        }
    }
    if (perms) {
        printf("perms: %d\n", perms);
    }
    return 0;
}
```