From a21a206c89409c3d1418e1e69e0562f621517dcf Mon Sep 17 00:00:00 2001
From: Timo Kreuzer <timo.kreuzer@reactos.org>
Date: Mon, 14 Oct 2024 00:03:54 +0300
Subject: [PATCH] [UCRT] Add workaround for va_arg warning about type promotion

---
 .../ucrt/inc/corecrt_internal_stdio_output.h    | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/sdk/lib/ucrt/inc/corecrt_internal_stdio_output.h b/sdk/lib/ucrt/inc/corecrt_internal_stdio_output.h
index cde4af0e080..bb4d545d88c 100644
--- a/sdk/lib/ucrt/inc/corecrt_internal_stdio_output.h
+++ b/sdk/lib/ucrt/inc/corecrt_internal_stdio_output.h
@@ -30,16 +30,33 @@ namespace __crt_stdio_output {
 // reads the next argument of type T from the varargs list and updates the
 // va_list, just like va_arg does.  The 'peek' function returns the next argument
 // of type T, but does not modify the va_list.
+#if defined(__GNUC__) || defined(__clang__)
+template<typename T> struct _va_arg_promoted_tye { using type = T; };
+template<> struct _va_arg_promoted_tye<signed char> { using type = int; };
+template<> struct _va_arg_promoted_tye<unsigned char> { using type = int; };
+template<> struct _va_arg_promoted_tye<wchar_t> { using type = int; };
+template<> struct _va_arg_promoted_tye<short int> { using type = int; };
+template<> struct _va_arg_promoted_tye<short unsigned int> { using type = int; };
+#endif
+
 template <typename T>
 T read_va_arg(va_list& arglist) throw()
 {
+#if defined(__GNUC__) || defined(__clang__)
+    return (T)(va_arg(arglist, typename _va_arg_promoted_tye<T>::type));
+#else
     return va_arg(arglist, T);
+#endif
 }
 
 template <typename T>
 T peek_va_arg(va_list arglist) throw()
 {
+#if defined(__GNUC__) || defined(__clang__)
+    return (T)(va_arg(arglist, typename _va_arg_promoted_tye<T>::type));
+#else
     return va_arg(arglist, T);
+#endif
 }