### NAME

flush - Flush buffered output for a channel

### SYNOPSIS

flush channelId

### DESCRIPTION

Flushes any output that has been buffered for channelId.

ChannelId must be an identifier for an open channel such as a Tcl standard channel (stdout or stderr), the return value from an invocation of open or socket, or the result of a channel creation command provided by a Tcl extension. The channel must have been opened for writing.

If the channel is in blocking mode the command does not return until all the buffered output has been flushed to the channel. If the channel is in nonblocking mode, the command may return before all buffered output has been flushed; the remainder will be flushed in the background as fast as the underlying file or device is able to absorb it.

### SEE ALSO

file, open, socket, Tcl_StandardChannels

### KEYWORDS

blocking, buffer, channel, flush, nonblocking, output

    Copyright © 1993 The Regents of the University of California.
    Copyright © 1994-1996 Sun Microsystems, Inc.
    Copyright © 1995-1997 Roger E. Critchlow Jr.