if (num <= 0) return NULL;
+ /* We don't support shrinking the buffer. Note the memcpy that copies
+ * |old_len| bytes to the new buffer, below. */
+ if (num < old_len) return NULL;
+
if (realloc_debug_func != NULL)
realloc_debug_func(str, NULL, num, file, line, 0);
ret=malloc_ex_func(num,file,line);