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null.3tcl
Langue: en
Version: 2.2 (debian - 07/07/09)
Section: 3 (Bibliothèques de fonctions)
NAME
null - Create and manipulate null channelsSYNOPSIS
package require Tclpackage require memchan
null
DESCRIPTION
The command described here is only available in a not-yet released version of the package. Use the CVS to get the sources.
- null
- creates a null channel which absorbs everything written into it. Reading from it is not possible, or rather will always return zero bytes. These channels are essentially Tcl-specific variants of the null device for unixoid operating systems (/dev/null). Transfering the generated channel between interpreters is possible but does not make much sense.
OPTIONS
Memory channels created by null provide one additional option to set or query.- -delay ?milliseconds?
- A null channel is always writable and readable. This means that all fileevent-handlers will fire continuously. To avoid starvation of other event sources the events raised by this channel type have a configurable delay. This option is set in milliseconds and defaults to 5.
A null channel is always writable and never readable. This means that a writable fileevent-handler will fire continuously and a readable fileevent-handler never at all. The exception to the latter is only the destruction of the channel which will cause the delivery of an eof event to a readable handler.
SEE ALSO
memchan, fifo, fifo2, random, zeroKEYWORDS
null, in-memory channel, channel, i/oCOPYRIGHT
Copyright (c) 1996-2003 Andreas Kupries <andreas_kupries@users.sourceforge.net>
Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre