From cb5f4605238016aec79af3a4272d6f1d0a770b02 Mon Sep 17 00:00:00 2001
From: Mike Barcroft <mike@FreeBSD.org>
Date: Sat, 27 Oct 2001 20:11:10 +0000
Subject: [PATCH] Only provide function information in compile environments
 that support the C99 variable __func__ and never for C++.  Provide a more
 meaningful example in the assert(3) manual.

Reviewed by:	asmodai, bde
---
 lib/libc/gen/assert.c   | 15 ++++++++++-----
 lib/libstand/assert.c   | 11 +++++++----
 share/man/man3/assert.3 | 18 +++++++++---------
 sys/sys/cdefs.h         |  5 +++++
 4 files changed, 31 insertions(+), 18 deletions(-)

diff --git a/lib/libc/gen/assert.c b/lib/libc/gen/assert.c
index 9f265b71114..7cd4d0c95b7 100644
--- a/lib/libc/gen/assert.c
+++ b/lib/libc/gen/assert.c
@@ -45,14 +45,19 @@ __FBSDID("$FreeBSD$");
 #include <stdlib.h>
 
 void
-__assert(function, file, line, failedexpr)
-	const char *function, *file;
+__assert(func, file, line, failedexpr)
+	const char *func, *file;
 	int line;
 	const char *failedexpr;
 {
-	(void)fprintf(stderr,
-		      "assertion (%s) failed: function %s(), file %s:%d\n",
-		      failedexpr, function, file, line);
+	if (func == NULL)
+		(void)fprintf(stderr,
+		     "assertion (%s) failed: file %s:%d\n", failedexpr,
+		     file, line);
+	else
+		(void)fprintf(stderr,
+		     "assertion (%s) failed: function %s(), file %s:%d\n",
+		     failedexpr, func, file, line);
 	abort();
 	/* NOTREACHED */
 }
diff --git a/lib/libstand/assert.c b/lib/libstand/assert.c
index 9317dcf2be9..6d0ab89fa18 100644
--- a/lib/libstand/assert.c
+++ b/lib/libstand/assert.c
@@ -32,10 +32,13 @@ __FBSDID("$FreeBSD$");
 #include "stand.h"
 
 void
-__assert(const char *function, const char *file, int line,
-	 const char *expression)
+__assert(const char *func, const char *file, int line, const char *expression)
 {
-	printf("assertion (%s) failed: function %s(), file %s:%d\n",
-	       expression, function, file, line);
+	if (func == NULL)
+		printf("assertion (%s) failed: file %s:%d\n", expression,
+		    file, line);
+	else
+		printf("assertion (%s) failed: function %s(), file %s:%d\n",
+		    expression, func, file, line);
 	exit();
 }
diff --git a/share/man/man3/assert.3 b/share/man/man3/assert.3
index bb233228264..ec74ae391c6 100644
--- a/share/man/man3/assert.3
+++ b/share/man/man3/assert.3
@@ -72,22 +72,22 @@ as a macro
 .Xr cc 1
 option
 .Fl D Ns Dv NDEBUG ) .
-.Sh DIAGNOSTICS
-The following diagnostic message is written to
-.Em stderr
-if
-.Ar expression
-is false:
+.Sh EXAMPLES
+The assertion:
 .Bd -literal -offset indent
-"assertion (%s) failed: function %s(), file %s:%d\en", \e
-		    "expression", __func__, __FILE__, __LINE__);
+assert(1 == 0);
+.Ed
+.Pp
+generates a diagnostic message similar to the following:
+.Bd -literal -offset indent
+assertion (1 == 0) failed: function main(), file assertion.c:100
 .Ed
 .Sh SEE ALSO
 .Xr abort 3
 .Sh STANDARDS
 The
 .Fn assert
-macro confirms to
+macro conforms to
 .St -isoC-99 .
 .Sh HISTORY
 An
diff --git a/sys/sys/cdefs.h b/sys/sys/cdefs.h
index 8705ca21390..c674f5a414e 100644
--- a/sys/sys/cdefs.h
+++ b/sys/sys/cdefs.h
@@ -48,6 +48,11 @@
 #define	__END_DECLS
 #endif
 
+/* XXX: should have __STDC_VERSION__ < 199901 */
+#if !defined(__GNUC__) || defined(__cplusplus)
+#define	__func__	NULL
+#endif
+
 /*
  * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
  * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.