glibc/nptl/tst-thread-setspecific.c
Martin Sebor a1561c3bbe Add __attribute_access_none to disable GCC warnings [BZ #27714]
GCC 11 warns when a pointer to an uninitialized object is passed
to a function that takes a const-qualified argument.  This is done
on the assumption that most such functions read from the object.
For the rare case of a function that doesn't, GCC 11 extends
attribute access to add a new mode called none.

POSIX pthread_setspecific() is one such rare function that takes
a const void* argument but that doesn't read from the object it
points to.  To suppress the -Wmaybe-uninitialized issued by GCC
11 when the address of an uninitialized object is passed to it
(e.g., the result of malloc()), this change #defines
__attr_access_none in cdefs.h and uses the macro on the function
in sysdeps/htl/pthread.h and sysdeps/nptl/pthread.h.
2021-04-27 13:01:55 -06:00

44 lines
1.4 KiB
C

/* Test to verify that passing a pointer to an uninitialized object
to pthread_setspecific doesn't trigger bogus uninitialized warnings.
Copyright (C) 2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <pthread.h>
#include <stdlib.h>
/* Turn uninitialized warnings into errors to detect the problem.
See BZ #27714. */
#pragma GCC diagnostic push
#pragma GCC diagnostic error "-Wmaybe-uninitialized"
#pragma GCC diagnostic error "-Wuninitialized"
int do_test (void)
{
void *p = malloc (1); /* Deliberately uninitialized. */
pthread_setspecific (pthread_self (), p);
void *q = pthread_getspecific (pthread_self ());
return p == q;
}
#pragma GCC diagnostic pop
#define TEST_FUNCTION do_test ()
#include "../test-skeleton.c"