[Bug libfortran/25830] [libgfortran] Optionally support multi-process locking

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830

--- Comment #7 from CVS Commits  ---
The master branch has been updated by Nick Clifton :

https://gcc.gnu.org/g:e6cbe9654d14588f8bcaf267730fa4c694216eee

commit r10-7841-ge6cbe9654d14588f8bcaf267730fa4c694216eee
Author: Stephen Casner 
Date:   Tue Apr 21 10:44:32 2020 +0100

Since the pdp11-aout target does not support gdb, gdbserver or gprof these
should be excluded in configure.

PR 25830
* configure.ac (noconfigdirs): Exclude gdb & gprof for pdp11.
* configure: Rebuild.

[Bug libfortran/25830] [libgfortran] Optionally support multi-process locking

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830

Dominique d'Humieres  changed:

   What|Removed |Added

 Status|WAITING |RESOLVED
 Resolution|--- |WONTFIX

--- Comment #6 from Dominique d'Humieres  ---
> This PR did not get any attention for almost five years. Any point to keep it 
> open?

No feed-back. Closing as WONTFIX.

[Bug libfortran/25830] [libgfortran] Optionally support multi-process locking

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830

Dominique d'Humieres  changed:

   What|Removed |Added

 Status|NEW |WAITING

--- Comment #5 from Dominique d'Humieres  ---
This PR did not get any attention for almost five years. Any point to keep it
open?

[Bug libfortran/25830] [libgfortran] Optionally support multi-process locking

[jb at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830

--- Comment #4 from Janne Blomqvist jb at gcc dot gnu.org 2011-04-25 16:41:26 
UTC ---
Some writings arguing that POSIX locking is more or less fundamentally broken:

http://0pointer.de/blog/projects/locking.html

http://0pointer.de/blog/projects/locking2.html

http://www.samba.org/samba/news/articles/low_point/tale_two_stds_os2.html

AFAICS, if gfortran is to eventually support multi-image IO in the context of
Co-array Fortran as in the TR

http://j3-fortran.org/doc/meeting/192/10-166.pdf ,

it is possible to implement all of this without relying on POSIX locking
(fcntl) for synchronization, instead using the existing IPC channels that
co-arrays provide. 

That being said, it might be necessary to do a fcntl lock+unlock at appropriate
places in order to force the NFS client to flush dirty bytes to the server;
alternatives to using fcntl() to force NFS flushing is fsync or a close+reopen
of the POSIX file descriptor. Close+reopen does have the nice property of being
portable and not relying on a working NFS locking implementation.

FWIW, one strange thing about the 10-166 TR is that there is no mention of
stream access, which AFAICS is suited to parallel access just like direct
access.

[Bug libfortran/25830] [libgfortran] Optionally support multi-process locking

[burnus at gcc dot gnu dot org]

--- Comment #3 from burnus at gcc dot gnu dot org  2008-11-20 15:52 ---
Other compilers have the SHARE= specifier for OPEN and INQUIRE, e.g. Intel or
HP. I'm not sure it is needed, but one could consider supporting it as well
when implementing this option.

http://www.intel.com/software/products/compilers/docs/flin/main_for/lref_for/source_files/rflioop.htm

I think Fortran 2008 does not allow to such access which makes it a non-issue
in terms of the standard, including for coarrays, but still this is a not so
rarely requested feature. (But one has to be careful as a user otherwise the
program might read/write garbage.)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830

[Bug libfortran/25830] [libgfortran] Optionally support multi-process locking

[jb at gcc dot gnu dot org]

--- Comment #1 from jb at gcc dot gnu dot org  2006-01-17 22:07 ---
Change severity to enhancement.


-- 

jb at gcc dot gnu dot org changed:

   What|Removed |Added

   Severity|normal  |enhancement


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830

[Bug libfortran/25830] [libgfortran] Optionally support multi-process locking

[pinskia at gcc dot gnu dot org]

--- Comment #2 from pinskia at gcc dot gnu dot org  2006-01-17 23:33 ---
Coonfirmed.


-- 

pinskia at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
 Ever Confirmed|0   |1
   Last reconfirmed|-00-00 00:00:00 |2006-01-17 23:33:50
   date||


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25830