Mercurial > hg > octave-lyh > gnulib-hg
changeset 16198:79e42746e843
doc: cover st_ino issues once; add OpenVMS etc.
* doc/posix-functions/stat.texi (stat):
* doc/posix-functions/lstat.texi (lstat):
* doc/posix-functions/fstatat.texi (fstatat):
* doc/posix-functions/fstat.texi (fstat):
Move general 'struct stat' stuff to sys_stat.texi,
leaving behind a pointer.
* doc/posix-headers/sys_stat.texi (sys/stat.h):
Merge duplicate info about 'struct stat' problems into here.
Mention issues with OpenVMS, GNU/Linux NFS, NetApp, ClearCase,
and suggest partial workarounds.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Sat, 31 Dec 2011 13:38:25 -0800 |
parents | 98a6ed2516bf |
children | 162e917fdda6 |
files | ChangeLog doc/posix-functions/fstat.texi doc/posix-functions/fstatat.texi doc/posix-functions/lstat.texi doc/posix-functions/stat.texi doc/posix-headers/sys_stat.texi |
diffstat | 6 files changed, 54 insertions(+), 18 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,17 @@ 2011-12-31 Paul Eggert <eggert@cs.ucla.edu> + doc: cover st_ino issues once; add OpenVMS etc. + * doc/posix-functions/stat.texi (stat): + * doc/posix-functions/lstat.texi (lstat): + * doc/posix-functions/fstatat.texi (fstatat): + * doc/posix-functions/fstat.texi (fstat): + Move general 'struct stat' stuff to sys_stat.texi, + leaving behind a pointer. + * doc/posix-headers/sys_stat.texi (sys/stat.h): + Merge duplicate info about 'struct stat' problems into here. + Mention issues with OpenVMS, GNU/Linux NFS, NetApp, ClearCase, + and suggest partial workarounds. + same-inode: port to OpenVMS * lib/same-inode.h (SAME_INODE): Port to OpenVMS by checking all three st_ino values.
--- a/doc/posix-functions/fstat.texi +++ b/doc/posix-functions/fstat.texi @@ -20,6 +20,8 @@ Portability problems not fixed by Gnulib: @itemize @item +@xref{sys/stat.h}, for general portability problems with @code{struct stat}. +@item On Cygwin, @code{fstat} applied to the file descriptors 0 and 1, returns different @code{st_ino} values, even if standard input and standard output are not redirected and refer to the same terminal.
--- a/doc/posix-functions/fstatat.texi +++ b/doc/posix-functions/fstatat.texi @@ -30,9 +30,5 @@ Portability problems not fixed by Gnulib: @itemize @item -On Windows platforms (excluding Cygwin), @code{st_ino} is always 0. -@item -On some file systems, @code{st_size} contains bogus information for -symlinks; use the gnulib module areadlink-with-size for a better way -to get symlink contents. +@xref{sys/stat.h}, for general portability problems with @code{struct stat}. @end itemize
--- a/doc/posix-functions/lstat.texi +++ b/doc/posix-functions/lstat.texi @@ -28,15 +28,5 @@ Portability problems not fixed by Gnulib: @itemize @item -On Windows platforms (excluding Cygwin), @code{st_ino} is always 0. -@item -Because of the definition of @code{struct stat}, it is not possible to -portably replace @code{stat} via an object-like macro. Therefore, -expressions such as @code{(islnk ? lstat : stat) (name, buf)} are not -portable, and should instead be written @code{islnk ? lstat (name, -buf) : stat (name, buf)}. -@item -On some file systems, @code{st_size} contains bogus information for -symlinks; use the gnulib module areadlink-with-size for a better way -to get symlink contents. +@xref{sys/stat.h}, for general portability problems with @code{struct stat}. @end itemize
--- a/doc/posix-functions/stat.texi +++ b/doc/posix-functions/stat.texi @@ -25,11 +25,11 @@ Portability problems not fixed by Gnulib: @itemize @item +@xref{sys/stat.h}, for general portability problems with @code{struct stat}. +@item Cygwin's @code{stat} function sometimes sets @code{errno} to @code{EACCES} when @code{ENOENT} would be more appropriate. @item -On Windows platforms (excluding Cygwin), @code{st_ino} is always 0. -@item Because of the definition of @code{struct stat}, it is not possible to portably replace @code{stat} via an object-like macro. Therefore, expressions such as @code{(islnk ? lstat : stat) (name, buf)} are not
--- a/doc/posix-headers/sys_stat.texi +++ b/doc/posix-headers/sys_stat.texi @@ -36,4 +36,40 @@ @item The macro @code{S_IFBLK} is missing on some platforms: MSVC 9. +@item +On Windows platforms (excluding Cygwin), @code{st_ino} is always 0. +@item +On OpenVMS, @code{st_ino} is an array of three @code{ino_t} values, +not a single value. +@item +To partially work around the previous two problems, you can test for +nonzero @code{st_ino} and use the Gnulib @code{same-inode} module to +compare nonzero values. For example, @code{(a.st_ino && SAME_INODE +(a, b))} is true if the @code{struct stat} values @code{a} and +@code{b} are known to represent the same file, @code{(a.st_ino && +!SAME_INODE (a, b))} is true if they are known to represent different +files, and @code{!a.st_ino} is true if it is not known whether they +represent different files. +@item +On some platforms, two different files may have the same @code{st_dev} +and @code{st_ino} values, even when @code{st_ino} is nonzero: +@itemize +@item +GNU/Linux NFS servers that export all local file systems as a single +NFS file system, if a local @code{st_dev} exceeds 255, or if a local +@code{st_ino} exceeds 16777215. +@item +Network Appliance NFS servers in snapshot directories; see Network +Appliance bug #195. +@item +ClearCase MVFS; see bug id ATRia04618. @end itemize +One partial workaround is to compare other file metadata such as +@code{st_mode} and @code{st_mtime} to detect this bug, but this +approach does not work on files whose metadata are being changed by +other programs. +@item +On some file systems, @code{st_size} contains bogus information for +symlinks; use the Gnulib module @code{areadlink-with-size} for a +better way to get symlink contents. +@end itemize