hi.c

/* gcc hi.c -o hi -lcrypto */

#include <stdlib.h>
#include <stdio.h>
#include <openssl/crypto.h>

int
main(int argc, char *argv[])
{
	void *(*openssl_malloc)(size_t), (*openssl_free)(void *);
	CRYPTO_get_mem_functions(&openssl_malloc, NULL, &openssl_free);
	printf("system malloc: %p   system free: %p\n", malloc, free);
	printf("openssl malloc: %p  openssl free: %p\n", openssl_malloc,
			openssl_free);
	return 0;
}

output

system malloc: 0x7fff8f3f8252   system free: 0x7fff8f3f7ee4
openssl malloc: 0x7fff8f3f8252  openssl free: 0x7fff8f3f7ee4