trace-mallocs.c

#include <dlfcn.h>

static int mallocs_active = 0;

void *malloc(size_t size) {
  void * (*real_malloc)(size_t);
  real_malloc = dlsym(RTLD_NEXT, "malloc");

  mallocs_active++;
  void *ptr = real_malloc(size);
  fprintf(stderr, "DEBUG: malloc(%zu) = %p, pointers=%i\n", size, ptr, mallocs_active);

  return ptr;
}

void free(void *ptr) {
  void * (*real_free)(void *ptr);
  real_free = dlsym(RTLD_NEXT, "free");

  mallocs_active--;
  fprintf(stderr, "DEBUG: free(%p), pointers=%i\n", ptr, mallocs_active);

  real_free(ptr);
}