Tracing version of malloc

It was a small victory, but after quite a bit of fiddling I managed to get #define to do my bidding! This seemed to be much more fiddly than I had expected. Still, it's working as the following example shows:

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

void * test3 (size_t size, char *file, int line)
{
    void *p;

    p = malloc (size);
    printf("test3: %zu %s %d %p\n", size, file, line, p);

    return p;
}

#define test1(s)                              \
    test3((s), __FILE__, __LINE__)

int main (int argc, char **argv)
{
    void *p;

    p = test1(1024); 

    printf("%p\n", p);

    free (p);
    return 0;
}

The great thing about this is that you can now hash define malloc() to include tracing information, so you can trace out memory allocations and of course free(). This can be useful for debugging purposes.

So, to be specific:

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

void * malloc2 (size_t size, char *file, int line)
{
    void *p;

    p = malloc (size);
    printf("test3: %zu %s %d %p\n", size, file, line, p);

    return p;
}

#define malloc(s)                              \
    malloc2((s), __FILE__, __LINE__)

int main (int argc, char **argv)
{
    void *p;

    p = malloc(1024); 

    printf("%p\n", p);

    free (p);
    return 0;
}

Of course you can do the same thing for free().