/usr/share/perl/5.14.2/IO/Select.pod is in perl-doc 5.14.2-6ubuntu2.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 | =head1 NAME
IO::Select - OO interface to the select system call
=head1 SYNOPSIS
use IO::Select;
$s = IO::Select->new();
$s->add(\*STDIN);
$s->add($some_handle);
@ready = $s->can_read($timeout);
@ready = IO::Select->new(@handles)->can_read(0);
=head1 DESCRIPTION
The C<IO::Select> package implements an object approach to the system C<select>
function call. It allows the user to see what IO handles, see L<IO::Handle>,
are ready for reading, writing or have an exception pending.
=head1 CONSTRUCTOR
=over 4
=item new ( [ HANDLES ] )
The constructor creates a new object and optionally initialises it with a set
of handles.
=back
=head1 METHODS
=over 4
=item add ( HANDLES )
Add the list of handles to the C<IO::Select> object. It is these values that
will be returned when an event occurs. C<IO::Select> keeps these values in a
cache which is indexed by the C<fileno> of the handle, so if more than one
handle with the same C<fileno> is specified then only the last one is cached.
Each handle can be an C<IO::Handle> object, an integer or an array
reference where the first element is an C<IO::Handle> or an integer.
=item remove ( HANDLES )
Remove all the given handles from the object. This method also works
by the C<fileno> of the handles. So the exact handles that were added
need not be passed, just handles that have an equivalent C<fileno>
=item exists ( HANDLE )
Returns a true value (actually the handle itself) if it is present.
Returns undef otherwise.
=item handles
Return an array of all registered handles.
=item can_read ( [ TIMEOUT ] )
Return an array of handles that are ready for reading. C<TIMEOUT> is
the maximum amount of time to wait before returning an empty list, in
seconds, possibly fractional. If C<TIMEOUT> is not given and any
handles are registered then the call will block.
=item can_write ( [ TIMEOUT ] )
Same as C<can_read> except check for handles that can be written to.
=item has_exception ( [ TIMEOUT ] )
Same as C<can_read> except check for handles that have an exception
condition, for example pending out-of-band data.
=item count ()
Returns the number of handles that the object will check for when
one of the C<can_> methods is called or the object is passed to
the C<select> static method.
=item bits()
Return the bit string suitable as argument to the core select() call.
=item select ( READ, WRITE, EXCEPTION [, TIMEOUT ] )
C<select> is a static method, that is you call it with the package name
like C<new>. C<READ>, C<WRITE> and C<EXCEPTION> are either C<undef> or
C<IO::Select> objects. C<TIMEOUT> is optional and has the same effect as
for the core select call.
The result will be an array of 3 elements, each a reference to an array
which will hold the handles that are ready for reading, writing and have
exceptions respectively. Upon error an empty list is returned.
=back
=head1 EXAMPLE
Here is a short example which shows how C<IO::Select> could be used
to write a server which communicates with several sockets while also
listening for more connections on a listen socket
use IO::Select;
use IO::Socket;
$lsn = IO::Socket::INET->new(Listen => 1, LocalPort => 8080);
$sel = IO::Select->new( $lsn );
while(@ready = $sel->can_read) {
foreach $fh (@ready) {
if($fh == $lsn) {
# Create a new socket
$new = $lsn->accept;
$sel->add($new);
}
else {
# Process socket
# Maybe we have finished with the socket
$sel->remove($fh);
$fh->close;
}
}
}
=head1 AUTHOR
Graham Barr. Currently maintained by the Perl Porters. Please report all
bugs to <perl5-porters@perl.org>.
=head1 COPYRIGHT
Copyright (c) 1997-8 Graham Barr <gbarr@pobox.com>. All rights reserved.
This program is free software; you can redistribute it and/or
modify it under the same terms as Perl itself.
=cut
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