__builtin_object_size.3 revision 1.6
$NetBSD: __builtin_object_size.3,v 1.6 2010/12/16 17:50:39 jruoho Exp $
Copyright (c) 2007 The NetBSD Foundation, Inc.
All rights reserved.
This code is derived from software contributed to The NetBSD Foundation
by Christos Zoulas.
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 16, 2010 .Dt __BUILTIN_OBJECT_SIZE 3 .Os .Sh NAME .Nm __builtin_object_size .Nd return the size of the given object .Sh LIBRARY .Ft size_t .Fn __builtin_object_size "void *ptr" "int type" .Sh DESCRIPTION The .Fn __builtin_object_size function is a .Xr gcc 1 built-in function that returns the size of the .Fa ptr object if known at compile time and the object does not have any side effects. .Sh RETURN VALUES If the size of the object is not known or it has side effects the .Fn __builtin_object_size function returns: l -tag -width (size_t)-1 -offset indent t Dv (size_t)-1 for .Fa type .Dv 0 and .Dv 1 . t Dv (size_t)0 for .Fa type .Dv 2 and .Dv 3 . .El
Copyright (c) 2007 The NetBSD Foundation, Inc.
All rights reserved.
This code is derived from software contributed to The NetBSD Foundation
by Christos Zoulas.
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 16, 2010 .Dt __BUILTIN_OBJECT_SIZE 3 .Os .Sh NAME .Nm __builtin_object_size .Nd return the size of the given object .Sh LIBRARY .Ft size_t .Fn __builtin_object_size "void *ptr" "int type" .Sh DESCRIPTION The .Fn __builtin_object_size function is a .Xr gcc 1 built-in function that returns the size of the .Fa ptr object if known at compile time and the object does not have any side effects. .Sh RETURN VALUES If the size of the object is not known or it has side effects the .Fn __builtin_object_size function returns: l -tag -width (size_t)-1 -offset indent t Dv (size_t)-1 for .Fa type .Dv 0 and .Dv 1 . t Dv (size_t)0 for .Fa type .Dv 2 and .Dv 3 . .El
p If the size of the object is known, then the .Fn __builtin_object_size function returns the maximum size of all the objects that the compiler knows that they can be pointed to by .Fa ptr when .Fa type .Dv \*[Am] 2 == 0 , and the minimum size when .Fa type .Dv \*[Am] 2 != 0 . .Sh SEE ALSO .Xr gcc 1 , .Xr attribute 3 , .Xr ssp 3 .Sh HISTORY The .Fn __builtin_object_size appeared in .Tn GCC 4.1 .