323d4b6f68
These functions should print assertion violation messages and then
call abort(). They do really not return control flow afterwards.
Consider the declaration of the similar __assert_fail from glibc:
extern void __assert_fail (const char *__assertion,
const char *__file,
unsigned int __line,
const char *__function)
__THROW __attribute__ ((__noreturn__));
Bionic has __noreturn defined in sys/cdefs.h to be that GNU
noreturn attribute.
This patch has a practical value. Consider the following function:
void check(void* ptr) {
assert(ptr != NULL);
}
Without this patch applied, gcc (and presumably clang) shows even in
debug mode:
warning: unused parameter 'ptr' [-Wunused-parameter]
In release mode, NDEBUG is defined and assert() becomes a no-op, as
one should expect. Thus, the warning is shown correctly then.
Another code sample:
float array[2];
int i = 3;
...
assert(i < 2);
array[i] = 0;
gcc says,
warning: array subscript is below array bounds [-Warray-bounds]
In other words, without noreturn attribute, assertions do not
allow a compiler's static analyzer to properly understand
the preconditions.
Change-Id: I3be92e99787c528899cf243ed448c4730c00c45b
Signed-off-by: Vadim Markovtsev <gmarkhor@gmail.com>
65 lines
2.7 KiB
C
65 lines
2.7 KiB
C
/* $OpenBSD: assert.h,v 1.12 2006/01/31 10:53:51 hshoexer Exp $ */
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/* $NetBSD: assert.h,v 1.6 1994/10/26 00:55:44 cgd Exp $ */
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/*-
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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* (c) UNIX System Laboratories, Inc.
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* All or some portions of this file are derived from material licensed
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* to the University of California by American Telephone and Telegraph
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* Co. or Unix System Laboratories, Inc. and are reproduced herein with
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* the permission of UNIX System Laboratories, Inc.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)assert.h 8.2 (Berkeley) 1/21/94
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*/
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/*
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* Unlike other ANSI header files, <assert.h> may usefully be included
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* multiple times, with and without NDEBUG defined.
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*/
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#include <sys/cdefs.h>
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#undef assert
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#undef _assert
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#ifdef NDEBUG
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# define assert(e) ((void)0)
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# define _assert(e) ((void)0)
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#else
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# define _assert(e) assert(e)
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# if __ISO_C_VISIBLE >= 1999
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# define assert(e) ((e) ? (void)0 : __assert2(__FILE__, __LINE__, __func__, #e))
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# else
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# define assert(e) ((e) ? (void)0 : __assert(__FILE__, __LINE__, #e))
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# endif
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#endif
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__BEGIN_DECLS
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__dead void __assert(const char *, int, const char *) __noreturn;
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__dead void __assert2(const char *, int, const char *, const char *) __noreturn;
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__END_DECLS
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