GCC / Clang Cleanup

gcc-cleanup.c

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

#define discard __attribute__((cleanup(__cleanup_free)))

void __cleanup_free(void *p) {
    free(* (void **) p);
}

void hello() {
    discard char *freeme = NULL;

    if(!(freeme = malloc(42)))
        exit(EXIT_FAILURE);

    strcpy(freeme, "blabla");
    printf(">> %s\n", freeme);
}

int main(void) {
    hello();
}

valgrind

maxux@laptix /tmp $ valgrind ./freeme 
==26740== Memcheck, a memory error detector
==26740== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==26740== Using Valgrind-3.15.0 and LibVEX; rerun with -h for copyright info
==26740== Command: ./freeme
==26740== 
>> blabla
==26740== 
==26740== HEAP SUMMARY:
==26740==     in use at exit: 0 bytes in 0 blocks
==26740==   total heap usage: 2 allocs, 2 frees, 1,066 bytes allocated
==26740== 
==26740== All heap blocks were freed -- no leaks are possible
==26740== 
==26740== For lists of detected and suppressed errors, rerun with: -s
==26740== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 0 from 0)

c'est cool cet arrtibute