Module Name:    src
Committed By:   jruoho
Date:           Sun Dec 19 09:30:50 UTC 2010

Modified Files:
        src/distrib/sets/lists/comp: mi
        src/share/man/man3: Makefile
Added Files:
        src/share/man/man3: __builtin_return_address.3

Log Message:
Document the __builtin_return_address() GNU extension. Again this is well
justified due to the wide use of these non-standard extensions in the tree.


To generate a diff of this commit:
cvs rdiff -u -r1.1555 -r1.1556 src/distrib/sets/lists/comp/mi
cvs rdiff -u -r1.65 -r1.66 src/share/man/man3/Makefile
cvs rdiff -u -r0 -r1.1 src/share/man/man3/__builtin_return_address.3

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/distrib/sets/lists/comp/mi
diff -u src/distrib/sets/lists/comp/mi:1.1555 src/distrib/sets/lists/comp/mi:1.1556
--- src/distrib/sets/lists/comp/mi:1.1555	Sun Dec 19 08:10:07 2010
+++ src/distrib/sets/lists/comp/mi	Sun Dec 19 09:30:49 2010
@@ -1,4 +1,4 @@
-#	$NetBSD: mi,v 1.1555 2010/12/19 08:10:07 jruoho Exp $
+#	$NetBSD: mi,v 1.1556 2010/12/19 09:30:49 jruoho Exp $
 #
 # Note: don't delete entries from here - mark them as "obsolete" instead.
 #
@@ -4908,7 +4908,9 @@
 ./usr/share/man/cat3/__aligned.0		comp-c-catman		.cat
 ./usr/share/man/cat3/__alignof__.0		comp-c-catman		.cat
 ./usr/share/man/cat3/__arraycount.0		comp-c-catman		.cat
+./usr/share/man/cat3/__builtin_frame_address.0	comp-c-catman		.cat
 ./usr/share/man/cat3/__builtin_object_size.0	comp-c-catman		.cat
+./usr/share/man/cat3/__builtin_return_address.0	comp-c-catman		.cat
 ./usr/share/man/cat3/__cacheline_aligned.0	comp-c-catman		.cat
 ./usr/share/man/cat3/__constfunc.0		comp-c-catman		.cat
 ./usr/share/man/cat3/__dead.0			comp-c-catman		.cat
@@ -10997,7 +10999,9 @@
 ./usr/share/man/html3/__aligned.html		comp-c-htmlman		html
 ./usr/share/man/html3/__alignof__.html		comp-c-htmlman		html
 ./usr/share/man/html3/__arraycount.html		comp-c-htmlman		html
+./usr/share/man/html3/__builtin_frame_address.html	comp-c-htmlman		html
 ./usr/share/man/html3/__builtin_object_size.html	comp-c-htmlman		html
+./usr/share/man/html3/__builtin_return_address.html	comp-c-htmlman		html
 ./usr/share/man/html3/__cacheline_aligned.html	comp-c-htmlman		html
 ./usr/share/man/html3/__constfunc.html		comp-c-htmlman		html
 ./usr/share/man/html3/__dead.html		comp-c-htmlman		html
@@ -16886,7 +16890,9 @@
 ./usr/share/man/man3/__aligned.3		comp-c-man		.man
 ./usr/share/man/man3/__alignof__.3		comp-c-man		.man
 ./usr/share/man/man3/__arraycount.3		comp-c-man		.man
+./usr/share/man/man3/__builtin_frame_address.3	comp-c-man		.man
 ./usr/share/man/man3/__builtin_object_size.3	comp-c-man		.man
+./usr/share/man/man3/__builtin_return_address.3	comp-c-man		.man
 ./usr/share/man/man3/__cacheline_aligned.3	comp-c-man		.man
 ./usr/share/man/man3/__constfunc.3		comp-c-man		.man
 ./usr/share/man/man3/__dead.3			comp-c-man		.man

Index: src/share/man/man3/Makefile
diff -u src/share/man/man3/Makefile:1.65 src/share/man/man3/Makefile:1.66
--- src/share/man/man3/Makefile:1.65	Sun Dec 19 08:10:08 2010
+++ src/share/man/man3/Makefile	Sun Dec 19 09:30:50 2010
@@ -1,8 +1,9 @@
-#	$NetBSD: Makefile,v 1.65 2010/12/19 08:10:08 jruoho Exp $
+#	$NetBSD: Makefile,v 1.66 2010/12/19 09:30:50 jruoho Exp $
 #	@(#)Makefile	8.2 (Berkeley) 12/13/93
 
 MAN=	_DIAGASSERT.3 __CONCAT.3 __UNCONST.3 CMSG_DATA.3 \
-	__alignof__.3 __arraycount.3 __insn_barrier.3 \
+	__alignof__.3 __arraycount.3 \
+	__builtin_return_address.3 __insn_barrier.3 \
 	assert.3 attribute.3 bits.3 bitstring.3 \
 	cdefs.3 dirent.3 dlfcn.3 dl_iterate_phdr.3 end.3 \
 	fast_divide32.3 ffs32.3 gcq.3 \
@@ -15,6 +16,7 @@
 
 MLINKS+=__CONCAT.3 __STRING.3
 MLINKS+=__UNCONST.3 __UNVOLATILE.3
+MLINKS+=__builtin_return_address.3 __builtin_frame_address.3
 MLINKS+=attribute.3 __dead.3 \
 	attribute.3 __pure.3 \
 	attribute.3 __constfunc.3 \

Added files:

Index: src/share/man/man3/__builtin_return_address.3
diff -u /dev/null src/share/man/man3/__builtin_return_address.3:1.1
--- /dev/null	Sun Dec 19 09:30:50 2010
+++ src/share/man/man3/__builtin_return_address.3	Sun Dec 19 09:30:50 2010
@@ -0,0 +1,67 @@
+.\" $NetBSD: __builtin_return_address.3,v 1.1 2010/12/19 09:30:50 jruoho Exp $
+.\"
+.\" Copyright (c) 2010 Jukka Ruohonen <jruoho...@iki.fi>
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+.\" PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+.\" POSSIBILITY OF SUCH DAMAGE.
+.\"
+.Dd December 19, 2010
+.Dt __BUILTIN_RETURN_ADDRESS 3
+.Os
+.Sh NAME
+.Nm __builtin_return_address
+.Nd the return address of a function
+.Sh SYNOPSIS
+.Ft void *
+.Fn __builtin_return_address "unsigned int level"
+.Ft void *
+.Fn __builtin_frame_address "unsigned int level"
+.Sh DESCRIPTION
+The
+.Fn __builtin_return_address
+is a
+.Tn GNU
+extension for obtaining the return address of the current function
+or one of the callers of the current function.
+.Pp
+The parameter
+.Fa level
+specifies the number of frames that should be scanned up in the call stack.
+A value 0 returns the address of the current function,
+a value 1 requests the address of the caller of the current function,
+a value 2 asks for the address of the caller's caller, and so forth.
+If the top of the call stack has been reached, the function will return 0.
+Note also that on some architectures it is only possible
+to determine the address of the current function.
+In such cases a value 0 is returned.
+Thus, it is usually safe to only use the value 0 for
+.Fa level .
+.Pp
+The
+.Fn __builtin_frame_address
+behaves similarly, but returns the address of the function
+frame rather than the return address of the function.
+.Sh SEE ALSO
+.Xr gcc 1 ,
+.Xr __builtin_object_size 3
+.Sh CAVEATS
+These are non-standard, compiler-specific extensions.

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