ncurses 6.4 - patch 20231001

[ncurses.git] / ncurses / base / safe_sprintf.c

diff --git a/ncurses/base/safe_sprintf.c b/ncurses/base/safe_sprintf.c
index 3fff2e83c4df473cdc6e92ba888409ec08772b4d..c38931d105b2e7be988a2887e855b32a2ba71f9e 100644 (file)
--- a/ncurses/base/safe_sprintf.c
+++ b/ncurses/base/safe_sprintf.c
@@ -34,7 +34,7 @@
 #include <curses.priv.h>
 #include <ctype.h>
 
-MODULE_ID("$Id: safe_sprintf.c,v 1.35 2021/10/03 00:25:09 tom Exp $")
+MODULE_ID("$Id: safe_sprintf.c,v 1.36 2023/09/30 10:42:42 Ian.Abbott Exp $")
 
 #if USE_SAFE_SPRINTF
 
@@ -264,11 +264,18 @@ NCURSES_SP_NAME(_nc_printf_string) (NCURSES_SP_DCLx
 # if HAVE_VSNPRINTF
            /* SUSv2, 1997 */
            int used;
-           while ((used = vsnprintf(my_buffer, my_length, fmt, ap))
-                  >= (int) my_length) {
+
+           do {
+               va_list ap2;
+
+               begin_va_copy(ap2, ap);
+               used = vsnprintf(my_buffer, my_length, fmt, ap2);
+               end_va_copy(ap2);
+               if (used < (int) my_length)
+                   break;
                my_length = (size_t) ((3 * used) / 2);
                my_buffer = typeRealloc(char, my_length, my_buffer);
-           }
+           } while (my_buffer != NULL);
 # else
            /* ISO/ANSI C, 1989 */
            vsprintf(my_buffer, fmt, ap);