+CRYPTO_mem_ctrl() provides fine-grained control of memory leak tracking.
+To enable tracking call CRYPTO_mem_ctrl() with a B<mode> argument of
+the B<CRYPTO_MEM_CHECK_ON>.
+To disable tracking call CRYPTO_mem_ctrl() with a B<mode> argument of
+the B<CRYPTO_MEM_CHECK_OFF>.
+
+While checking memory, it can be useful to store additional context
+about what is being done.
+For example, identifying the field names when parsing a complicated
+data structure.
+OPENSSL_mem_debug_push() (which calls CRYPTO_mem_debug_push())
+attachs an identifying string to the allocation stack.
+This must be a global or other static string; it is not copied.
+OPENSSL_mem_debug_pop() removes identifying state from the stack.
+
+At the end of the program, calling CRYPTO_mem_leaks() or
+CRYPTO_mem_leaks_fp() will report all "leaked" memory, writing it
+to the specified BIO B<b> or FILE B<fp>. These functions return 1 if
+there are no leaks, 0 if there are leaks and -1 if an error occurred.
+
+CRYPTO_mem_leaks_cb() does the same as CRYPTO_mem_leaks(), but instead
+of writing to a given BIO, the callback function is called for each
+output string with the string, length, and userdata B<u> as the callback
+parameters.
+
+If the library is built with the C<crypto-mdebug> option, then one
+function, CRYPTO_get_alloc_counts(), and two additional environment
+variables, B<OPENSSL_MALLOC_FAILURES> and B<OPENSSL_MALLOC_FD>,
+are available.