From 1cec88d33a7fd9394e46e4a55c8c0105120061fd Mon Sep 17 00:00:00 2001
From: Heikki Korpela <heko@cvs.openbsd.org>
Date: Mon, 13 Aug 2001 16:54:10 +0000
Subject: - Note that unpromoted types should not be passed to va_arg   (see
 http://gcc.gnu.org/ml/gcc-patches/1999-09/msg00221.html) - Remove unused *p
 variable from example - Add a float example (mainly to point out that people
 shouldn't   use float because it's promoted to double) ok millert@

---
 share/man/man3/stdarg.3 | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

(limited to 'share/man/man3/stdarg.3')

diff --git a/share/man/man3/stdarg.3 b/share/man/man3/stdarg.3
index 01c12b8be15..061a8df504f 100644
--- a/share/man/man3/stdarg.3
+++ b/share/man/man3/stdarg.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: stdarg.3,v 1.7 2000/10/26 00:37:03 aaron Exp $
+.\"	$OpenBSD: stdarg.3,v 1.8 2001/08/13 16:54:09 heko Exp $
 .\"	$NetBSD: stdarg.3,v 1.3 1994/11/30 15:24:37 jtc Exp $
 .\"
 .\" Copyright (c) 1990, 1991, 1993
@@ -124,9 +124,28 @@ to
 If there is no next argument, or if
 .Fa type
 is not compatible with the type of the actual next argument
-(as promoted according to the default argument promotions),
+(as promoted according to the default argument promotions, see below),
 random errors will occur.
 .Pp
+If the type in question is one that gets promoted, the promoted type
+should be used as the argument to
+.Fn va_arg .
+The following describes which types are promoted (and to what):
+.Bl -dash -compact
+.It
+.Va short
+is promoted to
+.Va int
+.It
+.Va float
+is promoted to
+.Va double
+.It
+.Va char
+is promoted to
+.Va int
+.El
+.Pp
 The first use of the
 .Fn va_arg
 macro after that of the
@@ -154,8 +173,9 @@ associated with each format character based on the type.
 void foo(char *fmt, ...)
 {
 	va_list ap;
-	int d;
-	char c, *p, *s;
+	int d, c;
+	char *s;
+	double f;
 
 	va_start(ap, fmt);
 	while (*fmt)
@@ -169,9 +189,12 @@ void foo(char *fmt, ...)
 			printf("int %d\en", d);
 			break;
 		case 'c':			/* char */
-			c = va_arg(ap, char);
+			c = va_arg(ap, int);	/* promoted */
 			printf("char %c\en", c);
 			break;
+		case 'f':			/* float */
+			f = va_arg(ap, double); /* promoted */
+			printf("float %f\en", f);
 		}
 	va_end(ap);
 }
-- 
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