kc3-lang/gnulib/doc/posix-functions/aligned_alloc.texi

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  Date : 2025-02-08T14:31:04
  

  doc: some updates for glibc 2.41
  

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• doc/posix-functions/aligned_alloc.texi

• @node aligned_alloc
  @subsection @code{aligned_alloc}
  @findex aligned_alloc
  
  ISO C23 specification:@* @url{https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3220.pdf} section 7.24.3.1.
  
  POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9799919799/functions/aligned_alloc.html}
  
  Documentation:@* @uref{https://www.kernel.org/doc/man-pages/online/pages/man3/aligned_alloc.3.html,,man aligned_alloc}
  
  Gnulib module: aligned_alloc
  @mindex aligned_alloc
  
  Portability problems fixed by Gnulib:
  @itemize
  @item
  This function fails if the alignment argument is smaller than
  @code{sizeof (void *)} on some platforms:
  macOS 14, AIX 7.3.1.
  
  @item
  This function returns a null pointer if the requested size is
  not a multiple of the alignment:
  Solaris 11.4.
  
  @item
  This function returns a null pointer if the size argument is zero:
  macOS 15, AIX 7.3, Solaris 11.4.
  
  @item
  On some platforms, @code{aligned_alloc} crashes if the requested size is
  not a multiple of the alignment:
  AddressSanitizer (gcc 11.2 or clang 13).
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @item
  This function is missing on many older platforms:
  glibc 2.15, macOS 10.14, FreeBSD 6.4, NetBSD 7.1, OpenBSD 6.0, Minix 3.1.8, AIX 7.1, HP-UX 11.31, Solaris 11.3, Cygwin 1.7.x, mingw, MSVC 14, Android 8.1.
  
  @item
  If the alignment and size are absurdly large, this function crashes:
  @c https://sourceware.org/bugzilla/show_bug.cgi?id=32301
  glibc 2.41.
  @end itemize
  
  Gnulib has partial substitutes for @code{aligned_alloc}
  that do not crash even if the AddressSanitizer bug is present:
  
  @itemize
  @item
  @mindex alignalloc
  The Gnulib module @code{alignalloc} provides a portable function
  @code{alignalloc} that is a near-substitute for glibc
  @code{aligned_alloc}, except that the result must be freed
  with @code{alignfree} rather than plain @code{free}.
  
  @item
  @mindex aligned-malloc
  The Gnulib module @code{aligned-malloc} provides functions for
  allocating and freeing blocks of suitably aligned memory.
  
  @item
  @mindex pagealign_alloc
  The Gnulib module @code{pagealign_alloc} provides a similar API for
  allocating and freeing blocks of memory aligned on a system page boundary.
  @end itemize
  

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