[Boost-bugs] [Boost C++ Libraries] #2998: Make file_sink flushable

Subject: [Boost-bugs] [Boost C++ Libraries] #2998: Make file_sink flushable
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-05-07 01:02:40

#2998: Make file_sink flushable
-------------------------------------------------------------+--------------
 Reporter:  Andrew Schweitzer <a.schweitzer.grps_at_[hidden]>  |       Owner:  turkanis      
     Type:  Feature Requests                                 |      Status:  new           
Milestone:  Boost 1.39.0                                     |   Component:  iostreams     
  Version:  Boost 1.38.0                                     |    Severity:  Not Applicable
 Keywords:                                                   |  
-------------------------------------------------------------+--------------
 file_sink is hard to use as a debug log, since it does not flush.

 For example, when used when pushed into a filtering_ostream with cout, if
 flush is not called, characters don't appear on console or in file in a
 timely fashion. If flush is called, the characters on the console appear
 but not those in the file, because file_sink does not implement Flushable
 concept, and doesn't flush.

 This code:
     filtering_ostream fo;

     file_sink fsink("out.txt");
     tee_filter<file_sink> tee_fsink(fsink);
     fo.push(tee_fsink);

     fo.push(cout);

     fo << "some text";
     fo.flush();

 is very useful for arbitrary chains of debug logs, but not currently
 usable.

 The same issue applies to file, file_descriptor, and file_descriptor_sink.

 If there is some reason these classes should not be modified to made
 flushable, then it seems easy to make flushable_* versions. Example of
 this attached, which was copied from file.hpp.

 I also tried to add flushable_file_descriptor, by privately inheriting
 from file_descriptor, and adding a flush call which calls
 ::FlushFileBuffers on handle()... but so far that doesn't seem to work, so
 not attaching.

 Discussion at
 http://groups.google.com/group/boost-

 list/browse_thread/thread/4c07e7c255e8143a/b9003b1b83c5a4db?lnk=raot&pli=1

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/2998>
Boost C++ Libraries <http://www.boost.org/>
Boost provides free peer-reviewed portable C++ source libraries.