+
+/*
+ * Return a newly allocated option string. This string is to be used as the
+ * optstring argument of getopt_long(), see GETOPT(3). opt_count is the number
+ * of elements in the long_options array. Returns NULL if the string's
+ * allocation fails.
+ */
+LTTNG_HIDDEN
+char *utils_generate_optstring(const struct option *long_options,
+ size_t opt_count)
+{
+ int i;
+ size_t string_len = opt_count, str_pos = 0;
+ char *optstring;
+
+ /*
+ * Compute the necessary string length. One letter per option, two when an
+ * argument is necessary, and a trailing NULL.
+ */
+ for (i = 0; i < opt_count; i++) {
+ string_len += long_options[i].has_arg ? 1 : 0;
+ }
+
+ optstring = zmalloc(string_len);
+ if (!optstring) {
+ goto end;
+ }
+
+ for (i = 0; i < opt_count; i++) {
+ if (!long_options[i].name) {
+ /* Got to the trailing NULL element */
+ break;
+ }
+
+ optstring[str_pos++] = (char)long_options[i].val;
+ if (long_options[i].has_arg) {
+ optstring[str_pos++] = ':';
+ }
+ }
+
+end:
+ return optstring;
+}