defer.h

a lightweight defer feature C is missing.

hello world
bye world
peek-a-boo
freeing

OVERVIEW

defer is a common programming language feature (found in go, swift, zig...) that defers execution of corresponding expressions (though their parameters are executed immediately) until the surrounding funtion returns, in LIFO order.

It can be used for many purposes, but the most significant usage would to clean up heap-allocated variables.

Combining defer with malloc is a strong memory management strategy that everyone should consider at least once.

USAGE

Copy and paste defer.h and array.h file, include them, and you'll get simple three macros (alongside macros in array.h), DEFERRABLE, RETURN, and most importantly, defer.

hello words
freed two words

1. After the function curly brace opening, write DEFERRABLE; It declares necessary variables for defer to work.
2. defer(void(*)(void*), void*) takes a function pointer, and a pointer that passes onto the same function.
3. Use RETURN instead of the regular return; It evaluates the return expression, saves it, executes deffered functions that you've passed, and then return the previously saved return expression.