zarg

A minimalist C library for simple handling of command line arguments. 🚀

Example

How to implement zarg in a program.

#include <stdio.h>
#include <stdlib.h>
#include <zarg.h>

int main(int argc, char *argv[])
{
    Flag plus = { "add", 'a', true, "Add up numbers" };
    Flag encourage = { "encourage", 'e', false, "Encourage the user" };
    Flag flags[] = { plus, encourage, _FLAG };

    // Help dialogue
    if (zinit(argv, flags))
        return 0;

    int total = 0;

    char **numbers = flag_value(argv, plus);
    for (int i = 0; i < ppclen(numbers); i++)   // Do not use flag_count() here, this will inevitably lead to a memory leak.
        total += atoi(numbers[i]);
    free(numbers);              // Always call free() on the return of flag_value()
    printf("Your numbers sum up to %d!\n", total);

    if (flag_passed(argv, encourage))
        printf
            ("Great job! That's how one should pass command line arguments!\n");

    char **files = argument_value(argv, flags); // Get all arguments not in relation to any Flag
    if (ppclen(files) > 0) {
        printf("You also passed these files …\n");    // There were such arguments
        for (int i = 0; i < ppclen(files); i++)
            printf("- %s\n", files[i]);
        printf("... which will be completely ignored!\n");
    }
    free(files);                // Always call free() on the return of argument_value()

    return 0;
}

Compile.

$ gcc -Wall -fstack-protector -lzarg myzarg.c -o myzarg

Then execute:

$ ./myzarg --help
./myzarg [option]

Options
--help, -h        Show this dialogue
--add, -a [value] Add up numbers
--encourage, -e   Encourage the user

… or

$ ./myzarg --add 2 -a 40
Your numbers sum up to 42!

If you've had a bad day, add --encourage!

$ ./myzarg --encourage -a 40 -a 2
Your numbers sum up to 42!
Great job! That's how one should pass command line arguments!

Wait, can I pass input files?

$ ./myzarg -a 21 file.txt -a 21 another_file.txt -e a_third_file.txt an_image.jpg
Your numbers sum up to 42!
Great job! That's how one should pass command line arguments!
You also passed these files …
- file.txt
- another_file.txt
- a_third_file.txt
- an_image.jpg
... which will be completely ignored!

Sure thing!

Installation

Prerequisites

• make (v4.4+)
• gcc (v14.1+)

Compiling

To compile libzarg using make.

$ make build/libzarg.so

After building libzarg, execute the install rule with root privileges to install libzarg to your system.

# make install

Removal

Execute the uninstall rule with root privileges to completely remove libzarg from your system.

# make uninstall

Testing

Follow the installation instructions. Once finished, build the base testing binary using make.

$ make build/test

Now run the automated testing script

$ make test

… or test manually.

$ ./build/test --help

Documentation

To better understand functions and code provided by this library, open this site with your browser of choice.

If you want to view the documentation offline, use Doxygen. Just run the doc rule with make.

$ make doc

You can now view all documentation locally. A good entry point is ./build/doc/html/globals.html.