binutils-gdb/gnulib/import/flexmember.h
Paul E. Murphy 9c9d63b15a gnulib: update to 776af40e0
This fixes PR27184, a failure to compile gdb due to
cdefs.h being out of sync with glibc on ppc64le targets
which are compiled with -mabi=ieeelongdouble and glibc
2.32.

Likewise, update usage of _GL_ATTRIBUTE_FORMAT_PRINTF to
_GL_ATTRIBUTE_FORMAT_PRINTF_STANDARD.

Likewise, disable newly added rpl_free gnulib api in
gdbserver support libraries.

Likewise, undefine read/write macros before redefining them
on mingw targets.

Likewise, wrap C++ usage of free with GNULIB_NAMESPACE namespace
as needed.

Change-Id: I86517613c0d8ac8f5ea45bbc4ebe2b54a3aef29f
2021-02-05 13:35:20 -05:00

61 lines
2.5 KiB
C

/* Sizes of structs with flexible array members.
Copyright 2016-2021 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 General Public
License as published by the Free Software Foundation; either
version 3 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
General Public License for more details.
You should have received a copy of the GNU General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>.
Written by Paul Eggert. */
#include <stddef.h>
/* Nonzero multiple of alignment of TYPE, suitable for FLEXSIZEOF below.
On older platforms without _Alignof, use a pessimistic bound that is
safe in practice even if FLEXIBLE_ARRAY_MEMBER is 1.
On newer platforms, use _Alignof to get a tighter bound. */
#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
# define FLEXALIGNOF(type) (sizeof (type) & ~ (sizeof (type) - 1))
#else
# define FLEXALIGNOF(type) _Alignof (type)
#endif
/* Yield a properly aligned upper bound on the size of a struct of
type TYPE with a flexible array member named MEMBER that is
followed by N bytes of other data. The result is suitable as an
argument to malloc. For example:
struct s { int n; char d[FLEXIBLE_ARRAY_MEMBER]; };
struct s *p = malloc (FLEXSIZEOF (struct s, d, n * sizeof (char)));
FLEXSIZEOF (TYPE, MEMBER, N) is not simply (sizeof (TYPE) + N),
since FLEXIBLE_ARRAY_MEMBER may be 1 on pre-C11 platforms. Nor is
it simply (offsetof (TYPE, MEMBER) + N), as that might yield a size
that causes malloc to yield a pointer that is not properly aligned
for TYPE; for example, if sizeof (int) == alignof (int) == 4,
malloc (offsetof (struct s, d) + 3 * sizeof (char)) is equivalent
to malloc (7) and might yield a pointer that is not a multiple of 4
(which means the pointer is not properly aligned for struct s),
whereas malloc (FLEXSIZEOF (struct s, d, 3 * sizeof (char))) is
equivalent to malloc (8) and must yield a pointer that is a
multiple of 4.
Yield a value less than N if and only if arithmetic overflow occurs. */
#define FLEXSIZEOF(type, member, n) \
((offsetof (type, member) + FLEXALIGNOF (type) - 1 + (n)) \
& ~ (FLEXALIGNOF (type) - 1))