[x264-devel] x264_vfprintf: use va_copy

[Henrik Gramner]

x264 | branch: master | Henrik Gramner <henrik at gramner.com> | Mon Jul 27 00:08:38 2015 +0200| [53b3b747e22f53204f6efb5106ab4a5a8eb57626] | committer: Anton Mitrofanov

x264_vfprintf: use va_copy

It's undefined behavior to use the same va_list twice.

This most likely didn't cause any issues in practice since the string would
have to be larger than 4 KiB to trigger the fallback path.

Use workaround for ICL as it doesn't define va_copy even for C99.

> http://git.videolan.org/gitweb.cgi/x264.git/?a=commit;h=53b3b747e22f53204f6efb5106ab4a5a8eb57626
---

 common/osdep.c |    6 +++++-
 common/osdep.h |    4 ++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/common/osdep.c b/common/osdep.c
index 5347887..d3bcd41 100644
--- a/common/osdep.c
+++ b/common/osdep.c
@@ -141,8 +141,12 @@ int x264_vfprintf( FILE *stream, const char *format, va_list arg )
     {
         char buf[4096];
         wchar_t buf_utf16[4096];
+        va_list arg2;
+
+        va_copy( arg2, arg );
+        int length = vsnprintf( buf, sizeof(buf), format, arg2 );
+        va_end( arg2 );
 
-        int length = vsnprintf( buf, sizeof(buf), format, arg );
         if( length > 0 && length < sizeof(buf) )
         {
             /* WriteConsoleW is the most reliable way to output Unicode to a console. */
diff --git a/common/osdep.h b/common/osdep.h
index 2dfd00b..f997ed1 100644
--- a/common/osdep.h
+++ b/common/osdep.h
@@ -57,6 +57,10 @@
 #define S_ISREG(x) (((x) & S_IFMT) == S_IFREG)
 #endif
 
+#if !defined(va_copy) && defined(__INTEL_COMPILER)
+#define va_copy(dst, src) ((dst) = (src))
+#endif
+
 #if !defined(isfinite) && (SYS_OPENBSD || SYS_SunOS)
 #define isfinite finite
 #endif