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Date: Wed, 19 Apr 2023 15:56:43 +0200
From: Jens Gustedt <Jens.Gustedt@...ia.fr>
To: musl@...ts.openwall.com
Subject: [C23 divers headers 14/17] C23: allow va_start to receive only one
argument
C23 allows functions that only have ... and no other
arguments. Therefore the second argument to va_start, that was not
useful anymore, has been removed. For backwards compatibility it is
still possible to provide such an argument and the va_start macro has
to be adapted such that it is able to cope with one or two arguments.
We take care of this by using the new __VA_OPT__ preprocessing
feature, for which we also construct a feature test on the fly.
---
include/stdarg.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/include/stdarg.h b/include/stdarg.h
index 3256f805..38db6257 100644
--- a/include/stdarg.h
+++ b/include/stdarg.h
@@ -1,5 +1,5 @@
-#ifndef _STDARG_H
-#define _STDARG_H
+#ifndef __STDC_VERSION_STDARG_H__
+#define __STDC_VERSION_STDARG_H__ 202311L
#ifdef __cplusplus
extern "C" {
@@ -9,7 +9,10 @@ extern "C" {
#include <bits/alltypes.h>
-#define va_start(v,l) __builtin_va_start(v,l)
+#define va_start(...) __va_start1(__VA_ARGS__ , 0, )
+#define __va_start1(...) __va_start2(__VA_ARGS__)
+#define __va_start2(v, l, ...) __builtin_va_start(v, l)
+
#define va_end(v) __builtin_va_end(v)
#define va_arg(v,l) __builtin_va_arg(v,l)
#define va_copy(d,s) __builtin_va_copy(d,s)
--
2.34.1
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