typeof.3 revision 1.2 $NetBSD: typeof.3,v 1.2 2010/12/19 08:10:09 jruoho Exp $
Copyright (c) 2010 Jukka Ruohonen <jruohonen (at] 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 TYPEOF 3 .Os .Sh NAME .Nm typeof .Nd GNU extension for type of an expression .Sh SYNOPSIS .Ft type .Fn typeof "expression" .Sh DESCRIPTION The .Fn typeof construct can be used to obtain the type of an expression. The syntax is comparable to that of .Fn sizeof , but semantically .Fn typeof operates like a type name defined with .Em typedef . .Sh EXAMPLES The following is a typical example of a type-generic macro: d -literal -offset indent #define MAX(a, b) ({ \\ typeof(a) _a = (a); \\ typeof(b) _b = (b); \\ _a > _b ? _a : _b; \\ }) .Ed .Sh SEE ALSO .Xr gcc 1 , .Xr __alignof__ 3 , .Xr attribute 3 , .Xr offsetof 3 .Sh CAVEATS The .Fn typeof construct is a non-standard, compiler-specific extension.
Copyright (c) 2010 Jukka Ruohonen <jruohonen (at] 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 TYPEOF 3 .Os .Sh NAME .Nm typeof .Nd GNU extension for type of an expression .Sh SYNOPSIS .Ft type .Fn typeof "expression" .Sh DESCRIPTION The .Fn typeof construct can be used to obtain the type of an expression. The syntax is comparable to that of .Fn sizeof , but semantically .Fn typeof operates like a type name defined with .Em typedef . .Sh EXAMPLES The following is a typical example of a type-generic macro: d -literal -offset indent #define MAX(a, b) ({ \\ typeof(a) _a = (a); \\ typeof(b) _b = (b); \\ _a > _b ? _a : _b; \\ }) .Ed .Sh SEE ALSO .Xr gcc 1 , .Xr __alignof__ 3 , .Xr attribute 3 , .Xr offsetof 3 .Sh CAVEATS The .Fn typeof construct is a non-standard, compiler-specific extension.
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