oracular (3) IO::BufferedSelect.3pm.gz

Provided by: libio-bufferedselect-perl_1.0-3_all bug

NAME
       IO::BufferedSelect - Line-buffered select interface


SYNOPSIS
           use IO::BufferedSelect;
           my $bs = new BufferedSelect($fh1, $fh2);
           while(1)
           {
               my @ready = $bs->read_line();
               foreach(@ready)
               {
                   my ($fh, $line) = @$_;
                   my $fh_name = ($fh == $fh1 ? "fh1" : "fh2");
                   print "$fh_name: $line";
               }
           }


DESCRIPTION
       The "select" system call (and the "IO::Select" interface) allows us to process multiple streams
       simultaneously, blocking until one or more of them is ready for reading or writing.  Unfortunately, this
       requires us to use "sysread" and "syswrite" rather than Perl's buffered I/O functions.  In the case of
       reading, there are two issues with combining "select" with "readline": (1) "select" might block but the
       data we want is already in Perl's input buffer, ready to be slurped in by "readline"; and (2) "select"
       might indicate that data is available, but "readline" will block because there isn't a full $/-terminated
       line available.

       The purpose of this module is to implement a buffered version of the "select" interface that operates on
       lines, rather than characters.  Given a set of filehandles, it will block until a full line is available
       on one or more of them.

       Note that this module is currently limited, in that (1) it only does "select" for readability, not
       writability or exceptions; and (2) it does not support arbitrary line separators ($/): lines must be
       delimited by newlines.


CONSTRUCTOR
       new ( HANDLES )
           Create a "BufferedSelect" object for a set of filehandles.  Note that because this class buffers
           input from these filehandles internally, you should only use the "BufferedSelect" object for reading
           from them (you shouldn't read from them directly or pass them to other BufferedSelect instances).


METHODS
       read_line
       read_line ($timeout)
       read_line ($timeout, @handles)
           Block until a line is available on one of the filehandles.  If $timeout is "undef", it blocks
           indefinitely; otherwise, it returns after at most $timeout seconds.

           If @handles is specified, then only these filehandles will be considered; otherwise, it will use all
           filehandles passed to the constructor.

           Returns a list of pairs "[$fh, $line]", where $fh is a filehandle and $line is the line that was read
           (including the newline, ala "readline").  If the filehandle reached EOF, then $line will be undef.
           Note that "reached EOF" is to be interpreted in the buffered sense: if a filehandle is at EOF but
           there are newline-terminated lines in "BufferedSelect"'s buffer, "read_line" will continue to return
           lines until the buffer is empty.


SEE ALSO
       IO::Select


AUTHOR
       Antal Novak, <afn@cpan.org>


       Copyright (C) 2007 by Antal Novak

       This library is free software; you can redistribute it and/or modify it under the same terms as Perl
       itself, either Perl version 5.8.8 or, at your option, any later version of Perl 5 you may have available.