Defer.h

This is a simple C header wrapper for implementing defer statements similar to those found in Go. The defer.h header file provides a single macro, DEFER, which can be used to simplify resource management and ensure that resources are automatically cleaned up when they are no longer needed. The macro takes advantage of the cleanup attribute in gcc and clang. This repo is inspired by the work originally done by smokris and Baruch Even

Usage

DEFER

The DEFER macro is used to define a cleanup function that is called when the block of code containing the DEFER macro ends. It takes a single argument:

The code to execute when the block ends.

Example:

#include <stdio.h>
#include <stdlib.h>
#include "defer.h"

int main()
{
    int *resource = malloc(sizeof(int));
    *resource = 42;
    printf("Allocated resource %d\n", *resource);
    DEFER({
        printf("Cleaning up resource %d\n", *resource);
        free(resource);
    });

    // Do something with the resource
    printf("Using resource %d\n", *resource);
    return 0;
    // End of block - resource is automatically cleaned up here
}

In this example, we use the DEFER macro to automatically free a dynamically allocated integer when the block of code containing the DEFER macro ends. The cleanup function defined by the DEFER macro frees the resource and prints a message to the console.

By using the DEFER macro in this way, we can simplify resource management and ensure that resources are automatically cleaned up when they are no longer needed.

When the block ends, the cleanup function defined by the DEFER macro is automatically called, freeing the resource and ensuring that it is not leaked.

By using the DEFER macro in this way, we can simplify resource management and ensure that resources are automatically cleaned up when they are no longer needed.