Welcome to the c-result-type wiki!

This project aims to provide a Golang-like error as values experience in C. The main goal is to provide a way to handle errors in a more expressive way, without the need to use the errno variable, the return value of the function or argument pointers to check if it was successful.

You can check out the blog post discussing this topic at this link

Quick Start

1. Copy result.h to your project
2. Make sure that result.h is in the include path of your project
3. Import the result.h file in your source code

#include "result.h"

GEN_RESULT(int);

Res_int divide(int a, int b) {
    if (b == 0) {
        return (Res_int) {0, InternalError("cannot divide by zero!\n")};
    }
    return (Res_int) {a/b, NoError()};
}

int main(){
    int a, b;
    scanf("%d %d", &a, &b);
    DESTRUCT(res, err, divide(a, b));
    if (err.code != NIL) {
        printf("%s\n", err.message);
    }
    printf("%d / %d = %d\n", a, b, res);
}

Available macros:

GEN_RESULT(type)

Generate a result type for the specified type, named Res_'type'

GEN_RESULT_DEF(type,Name)

Generate a result type for the specified type, named 'Name'

auto

Automatically infer the type of a variable

auto a = divide(10, 2);
if (a.err.code != NIL) {
    printf("%s\n", a.err.message);
}
printf("%d %s\n", a.val, a.err.message);

DESTRUCT(var_val, var_err, Result)

Destructure from 'Result', defining and initializing 'var_val' and 'var_err'

DESTRUCT(id, err, deleteUser(10));

DESTRUCT_CP(var_val, var_err, Result)

Destructure from 'Result', initializing 'var_val' and 'var_err'

int id;
Error err;
DESTRUCT_CP(id, err, deleteUser(10));

DESTRUCT_VAL(var_val, var_err, Result)

Destructure from 'Result', defining 'val_val' and initializing 'var_val' and 'var_err'

Error err;
DESTRUCT_VAL(id, err, deleteUser(10));

DESTRUCT_ERR(var_val, var_err, Result)

Destructure from 'Result', defining 'val_err' and initializing 'var_val' and 'var_err'

int id;
DESTRUCT_ERR(id, err, deleteUser(10));

_

Ignores the result of a function

DESTRUCT(_, err, deleteUser(10));