diff --git a/thirdparty/gbstring.c b/thirdparty/gbstring.c
index 4be85ed..badffaa 100644
--- a/thirdparty/gbstring.c
+++ b/thirdparty/gbstring.c
@@ -89,7 +89,19 @@ gbs gbs_new(char const *str) {
   size_t len = str ? strlen(str) : 0;
   return gbs_newlen(str, len);
 }
-
+gbs gbs_newvprintf(const char *fmt, va_list ap) {
+  gbs s;
+  s = gbs_catvprintf(NULL, fmt, ap);
+  return s;
+}
+gbs gbs_newprintf(char const *fmt, ...) {
+  gbs s;
+  va_list ap;
+  va_start(ap, fmt);
+  s = gbs_catvprintf(NULL, fmt, ap);
+  va_end(ap);
+  return s;
+}
 void gbs_free(gbs str) {
   if (str == NULL)
     return;
@@ -227,9 +239,7 @@ gbs gbs_catvprintf(gbs s, const char *fmt, va_list ap) {
   }
   if (s == NULL)
     return NULL;
-  va_copy(cpy, ap);
-  vsnprintf(s + old_len, (size_t)required + 1, fmt, cpy);
-  va_end(cpy);
+  vsnprintf(s + old_len, (size_t)required + 1, fmt, ap);
   return s;
 }
 
diff --git a/thirdparty/gbstring.h b/thirdparty/gbstring.h
index 2ab8bc9..9d34b76 100644
--- a/thirdparty/gbstring.h
+++ b/thirdparty/gbstring.h
@@ -8,6 +8,12 @@ typedef char *gbs;
 gbs gbs_newcap(size_t cap);
 gbs gbs_newlen(void const *str, size_t len);
 gbs gbs_new(char const *str);
+gbs gbs_newvprintf(const char *fmt, va_list ap);
+gbs gbs_newprintf(char const *fmt, ...)
+#ifdef __GNUC__
+    __attribute__((format(printf, 1, 2)))
+#endif
+    ;
 void gbs_free(gbs str);
 
 gbs gbs_dup(gbs const str);
@@ -21,6 +27,12 @@ void gbs_clear(gbs str);
 gbs gbs_catlen(gbs str, void const *other, size_t len);
 gbs gbs_cat(gbs str, char const *other);
 gbs gbs_catgbs(gbs str, gbs const other);
+gbs gbs_catvprintf(gbs str, const char *fmt, va_list ap);
+gbs gbs_catprintf(gbs str, char const *fmt, ...)
+#ifdef __GNUC__
+    __attribute__((format(printf, 2, 3)))
+#endif
+    ;
 
 gbs gbs_cpylen(gbs str, char const *cstr, size_t len);
 gbs gbs_cpy(gbs str, char const *cstr);
@@ -31,11 +43,4 @@ bool gbs_equal(gbs const lhs, gbs const rhs);
 
 gbs gbs_trim(gbs str, char const *cut_set);
 
-gbs gbs_catvprintf(gbs str, const char *fmt, va_list ap);
-gbs gbs_catprintf(gbs str, char const *fmt, ...)
-#ifdef __GNUC__
-    __attribute__((format(printf, 2, 3)))
-#endif
-    ;
-
 size_t gbs_totalmemused(gbs const str);