+ return cat(dest, str, strnlen(str, n));
+}
+
+bool
+ralloc_str_append(char **dest, const char *str,
+ size_t existing_length, size_t str_size)
+{
+ char *both;
+ assert(dest != NULL && *dest != NULL);
+
+ both = resize(*dest, existing_length + str_size + 1);
+ if (unlikely(both == NULL))
+ return false;
+
+ memcpy(both + existing_length, str, str_size);
+ both[existing_length + str_size] = '\0';
+
+ *dest = both;