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

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  Date : 2025-01-05T17:45:41
  

  utimensat: mention Linux kernel bug with CIFS
  
  * doc/posix-functions/utimensat.texi (utimensat):
  Mention Linux kernel bug reported by Bruno Haible in:
  https://lists.gnu.org/r/bug-tar/2024-12/msg00004.html
  

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• doc/posix-functions/utimensat.texi

• @node utimensat
  @subsection @code{utimensat}
  @findex utimensat
  
  POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9799919799/functions/utimensat.html}
  
  Gnulib module: utimensat
  @mindex utimensat
  
  Portability problems fixed by Gnulib:
  @itemize
  @item
  This function is missing on some platforms:
  glibc 2.5, Mac OS X 10.5, FreeBSD 6.0, NetBSD 5.0, OpenBSD 3.8, Minix 3.1.8, AIX 5.1, HP-UX 11, Solaris 10, Cygwin 1.5.x, mingw, MSVC 14, Android 3.0.
  However, the replacement function may end up truncating timestamps to
  worse resolution than supported by the file system.  Furthermore, the
  replacement function is not safe to be used in libraries and is not
  multithread-safe.
  @item
  This function returns a bogus value instead of failing with
  @code{ENOSYS} on some platforms:
  Linux kernel 2.6.21.
  @item
  This function fails with @code{ENOSYS} if passed the flag
  @code{AT_SYMLINK_NOFOLLOW} on a regular file:
  Linux kernel 2.6.22.
  @item
  When using @code{UTIME_OMIT} or @code{UTIME_NOW}, some systems require
  the @code{tv_sec} argument to be 0, and don't necessarily handle all
  file permissions in the manner required by POSIX:
  Linux kernel 2.6.25.
  @item
  When using @code{UTIME_OMIT} for the modification time, but specifying
  an access time, some systems fail to update the change time:
  Linux kernel 2.6.32, macOS 14, NetBSD 10.0, Solaris 11.1.
  @item
  Out-of-range values of @code{tv_nsec} do not lead to a failure on some
  platforms:
  Linux kernel 2.6.22.19 on hppa, NetBSD 10.0.
  @item
  On some platforms, this function mis-handles a trailing slash:
  AIX 7.2.
  @end itemize
  
  Portability problems not fixed by Gnulib:
  @itemize
  @item
  On file systems mounted with the @code{noatime} attribute,
  this function might not modify the access time as requested:
  Linux kernel 6.9.
  @item
  This function ignores the flag @code{AT_SYMLINK_NOFOLLOW}:
  Linux kernel 6.8 on a CIFS file system.
  @item
  This function sets a slightly different time stamp than the requested one:
  @c https://dev.haiku-os.org/ticket/19213
  Haiku.
  @item
  On some platforms, timestamps of symbolic links cannot be modified, so
  the replacement fails with @code{ENOSYS} if passed the flag
  @code{AT_SYMLINK_NOFOLLOW} on a symlink.
  @item
  The mere act of using @code{lstat} modifies the access time of
  symlinks on some platforms, so @code{utimensat} with
  @code{AT_SYMLINK_NOFOLLOW} can only effectively change modification time:
  Cygwin.
  @item
  The mere act of using @code{stat} modifies the access time of
  directories on some platforms, so @code{utimensat} can only
  effectively change directory modification time:
  Cygwin 1.5.x.
  @end itemize
  
  @mindex fdutimensat
  The gnulib module @code{fdutimensat} provides a similar interface.
  

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