How can i explicitly hint Valgrind about intentially non freed memory

Question

I have a good number of memory allocations i just want to let die with the process because of complicated synchronisation issues and other convenience.

I don't want to write a suppression file.

Is there some C code that i can signal this to avoid false positives (not really false but unwanted). I know valgrind has an API but failed to find that.

Answer 1

One easy way to quiet valgrind would be store your "leaked" pointers in a process-lifetimed data structure so that valgrind reports them as "still reachable" rather than "definitely leaked". For example, in the code below, I call IgnoreThisLeak(leakMe) to keep valgrind from complaining that I never free my 100-byte allocation:

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

struct Node
{
   struct Node * _nextNode;
   void * _leakPtr;
};

static void IgnoreThisLeak(void * leakPtr)
{
   static struct Node * _tail = NULL;

   struct Node * n = malloc(sizeof(struct Node));
   n->_nextNode = _tail;
   n->_leakPtr  = leakPtr;
   _tail = n;
}

int main(int argc, char ** argv)
{
    int * leakMe = malloc(100);

    IgnoreThisLeak(leakMe);
    printf("leakMe=%p\n", leakMe);
    return 0;
}

Answer 2

Generating a suppression file will probably be the easiest way. Valgrind can generate the suppressions for you with --gen-supressions=all.