glibc/math/fgetexcptflg.c
Joseph Myers 4dfb9c9411 Make fallback fegetexceptflag work with generic fetestexceptflag.
The generic implementation of fetestexceptflag does:

int
fetestexceptflag (const fexcept_t *flagp, int excepts)
{
  /* Most versions of fegetexceptflag store exceptions in a form such
     that this works.  */
  return *flagp & excepts & FE_ALL_EXCEPT;
}

In the case where FE_ALL_EXCEPT is nonzero but exceptions may not be
supported at runtime, this only works if fegetexceptflag cleared all
the bits of FE_ALL_EXCEPT in *flagp; otherwise it accesses
uninitialized data.  This showed up as a failure of
math/test-fetestexceptflag for MIPS o32 soft-float.  This patch makes
the fallback fegetexceptflag store 0 (fexcept_t is an integer type
everywhere) so that this works.  (No bug report in Bugzilla because
this wasn't user-visible - at least, without using tools to detect
uninitialized memory use at runtime - without fetestexceptflag, which
is new in 2.25.)

Tested for MIPS o32 soft-float.

	* math/fgetexcptflg.c (__fegetexceptflag): Store 0 in fexcept_t
	object.
2017-01-12 01:52:37 +00:00

37 lines
1.3 KiB
C

/* Store current representation for exceptions.
Copyright (C) 1997-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
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
<http://www.gnu.org/licenses/>. */
#include <fenv.h>
#include <shlib-compat.h>
int
__fegetexceptflag (fexcept_t *flagp, int excepts)
{
/* Nothing to do. */
*flagp = 0;
return 0;
}
#if SHLIB_COMPAT (libm, GLIBC_2_1, GLIBC_2_2)
strong_alias (__fegetexceptflag, __old_fegetexceptflag)
compat_symbol (libm, __old_fegetexceptflag, fegetexceptflag, GLIBC_2_1);
#endif
versioned_symbol (libm, __fegetexceptflag, fegetexceptflag, GLIBC_2_2);
stub_warning (fegetexceptflag)