include the mcheck.h header file in all your .c files, and call mtrace as the first statement in main.
See also LD_DEBUG, MALLOC_CHECK_
2 pages link to mcheck:
lib/main.php:944: Notice: PageInfo: Cannot find action page
lib/main.php:839: Notice: PageInfo: Unknown action
lib/plugin/WlugLicense.php:99: Warning: Invalid argument supplied for foreach()