memchan(n)																memchan(n)

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NAME

       memchan - Create and manipulate memory channels

SYNOPSIS

       package require Tcl

       package require memchan

       memchan ?-initial-size len?

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DESCRIPTION

       This  manpage  documents both the overall package and the command memchan. The package itself provides a number of in-memory channels which
       can utilized to

       o      capture stream-like information in a natural way instead of using set and append to manipulate strings

       o      or to transfer data between interpreters, in the same thread or not.

COMMAND

       memchan ?-initial-size len?
	      creates a chunk-oriented in-memory channel and returns its handle. If an initial size is specified the system will pre-allocate  len
	      bytes  of  buffer space for the contents. This is no restriction on the ultimate size of the channel, it will always grow as much as
	      is necessary to accomodate the data written into it.

	      The channels created here can be transfered between interpreters in the same thread and between threads, but only as a whole. It	is
	      not possible to use them to create a bi- or unidirectional connection between two interpreters.

       Memory channels created by memchan provide two read-only options which can be queried via the standard fconfigure command. These are

       -length
	      The value of this option is the number of bytes currently stored in the queried memory channel.

       -allocated
	      The value of this option is the number of bytes currently allocated by the queried memory channel. This number is at least as big as
	      the value of -length.

       As the channels generated by memchan grow as necessary they are always writable. This means that a  writable  fileevent-handler	will  fire
       continuously.

       The  channels  are  also readable if they contain more than zero bytes and the seek location is not and the end of the channel. Under these
       conditions a readable fileevent-handler will fire continuously.

       Note that writing to such a channel usually occurs at the end, thus supressing readable events. This also means that  users  have  to  take
       care to seek the channel to a location before the end before trying to read data back.

SEE ALSO

       fifo, fifo2, null, random, zero

KEYWORDS

       channel, chunk, i/o, in-memory channel, memchan

COPYRIGHT

       Copyright (c) 1996-2003 Andreas Kupries <andreas_kupries@users.sourceforge.net>

Memory channels 							2.2								memchan(n)