kc3-lang/gnulib/doc/posix-headers/stdalign.texi

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• Hash : 086fbef2
  Author :
  Date : 2011-11-01T08:22:55
  

  * tests/test-stdalign.c (TEST_ALIGNMENT): Shrink back to 8.
  
  mingw supports alignments only up to 8 (!).  Reported by Bruno Haible in
  <http://lists.gnu.org/archive/html/bug-gnulib/2011-11/msg00006.html>.
  * doc/posix-headers/stdalign.texi (stdalign.h): Document this.
  

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• doc/posix-headers/stdalign.texi

• @node stdalign.h
  @section @file{stdalign.h}
  
  POSIX specification:@* Not in POSIX yet, but we expect it will be.
  ISO C1X @url{http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1570.pdf}
  sections 6.5.3.4, 6.7.5, 7.15.
  C++0X @url{http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2011/n3242.pdf}
  section 18.10.
  
  Gnulib module: stdalign
  
  Portability problems fixed by Gnulib:
  @itemize
  @item
  This header file is missing on most circa-2011 platforms.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @item
  @code{_Alignas} and @code{alignas} are not always supported;
  on platforms lacking support, the
  macro @code{__alignas_is_defined} is not defined.
  Supported compilers include GCC, IBM C, Sun C 5.11 and later,
  and MSVC 7.0 and later.
  @item
  Some compilers do not support alignment via
  @code{alignas}/@code{_Alignas} of @code{auto} variables (i.e.,
  variables on the stack).  They diagnose and ignore the alignment: Sun
  C 5.11.
  @item
  Some linkers do not support operands of @code{_Alignas}/@code{alignas}
  that are greater than 8: mingw.
  @item
  Some compilers require the operand of @code{_Alignas}/@code{alignas}
  to be a single integer constant, not an expression: MSVC 7.0 through
  at least 10.0.
  @item
  The Sun C 5.11 compiler sometimes mishandles the alignment of multiple
  external variables that are declared close together with
  @code{_Alignas}/@code{alignas}.  This compiler bug causes the Gnulib
  module @code{stdalign-tests} to fail.
  @item
  @code{<stdalign.h>} must be #included before @samp{_Alignas} and
  @samp{_Alignof} can be used.
  @item
  You cannot assume that @code{_Alignas} and @code{_Alignof} are reserved words;
  they might be macros.
  @end itemize
  

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