[Bug libstdc++/51701] New: Remove reference to Henry Suter's RWLock from documentation

[Bug libstdc++/51701] New: Remove reference to Henry Suter's RWLock from documentation

[jb at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51701

             Bug #: 51701
           Summary: Remove reference to Henry Suter's RWLock from
                    documentation
    Classification: Unclassified
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jb@gcc.gnu.org


In the libstdc++ manual at

http://gcc.gnu.org/onlinedocs/libstdc++/manual/ext_io.html

it says "If you want to access a filebuf's file descriptor to implement file
locking (e.g. using the fcntl() system call) then you might be interested in
Henry Suter's RWLock class. "

There are a couple issues with this RWLock class:

- The code has apparently disappeared from the internet, I was able to locate
it only via the Wayback machine.

- Having looked at the code, it is racy and wrong: 

1) For the code to operate correctly, opening a file and reading and writing
stuff from that file would need to be atomic. No target I'm aware of provides
such a guarantee.

2) It leaks memory; RWLockFileName is not deleted in the destructor.


Thus, I suggest that the sentence I quoted above should be removed.

[Bug libstdc++/51701] Remove reference to Henry Suter's RWLock from documentation

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51701

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011-12-29
         AssignedTo|unassigned at gcc dot       |redi at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

[Bug libstdc++/51701] Remove reference to Henry Suter's RWLock from documentation

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51701

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-12-29 15:31:05 UTC ---
For the record the code can be found at
http://web.archive.org/web/20070810183256/http://suter.home.cern.ch/suter/RWLock.html
but I agree that referring to it from the libstdc++ manual isn't very useful

[Bug libstdc++/51701] Remove reference to Henry Suter's RWLock from documentation

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51701

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-12-29 15:41:45 UTC ---
Author: redi
Date: Thu Dec 29 15:41:37 2011
New Revision: 182724

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=182724
Log:
    PR libstdc++/51701
    * doc/xml/manual/extensions.xml (Input and Output): Remove reference
    to RWLock class.

Modified:
    trunk/libstdc++-v3/ChangeLog
    trunk/libstdc++-v3/doc/xml/manual/extensions.xml

[Bug libstdc++/51701] Remove reference to Henry Suter's RWLock from documentation

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51701

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |documentation
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.7.0

--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-12-29 15:43:28 UTC ---
done