win32_common: fix windows_msg() with long messages

diff --git a/src/win32_common.c b/src/win32_common.c
index 514965b869091c8741519cedaad8f412afba0942..47f2df307375b5591a770e97b42ff41774f2160b 100644 (file)
--- a/src/win32_common.c
+++ b/src/win32_common.c
@@ -274,9 +274,12 @@ windows_msg(u32 code, const wchar_t *format, va_list va,
        size_t buflen = ARRAY_LEN(_buf);
        size_t ret;
        size_t n;
+       va_list va2;
 
 retry:
-       n = vsnwprintf(buf, buflen, format, va);
+       va_copy(va2, va);
+       n = vsnwprintf(buf, buflen, format, va2);
+       va_end(va2);
 
        if (n >= buflen)
                goto realloc;