tcl_createclosehandler(3tcl) [opensolaris man page]
Tcl_CreateCloseHandler(3TCL) Tcl Library Procedures Tcl_CreateCloseHandler(3TCL)__________________________________________________________________________________________________________________________________________________NAME
Tcl_CreateCloseHandler, Tcl_DeleteCloseHandler - arrange for callbacks when channels are closed
SYNOPSIS
#include <tcl.h>
void
Tcl_CreateCloseHandler(channel, proc, clientData)
void
Tcl_DeleteCloseHandler(channel, proc, clientData)
ARGUMENTS
Tcl_Channel channel (in) The channel for which to create or delete a close callback.
Tcl_CloseProc *proc (in) The procedure to call as the callback.
ClientData clientData (in) Arbitrary one-word value to pass to proc.
_________________________________________________________________DESCRIPTION
Tcl_CreateCloseHandler arranges for proc to be called when channel is closed with Tcl_Close or Tcl_UnregisterChannel, or using the Tcl
close command. Proc should match the following prototype:
typedef void Tcl_CloseProc(
ClientData clientData);
The clientData is the same as the value provided in the call to Tcl_CreateCloseHandler.
Tcl_DeleteCloseHandler removes a close callback for channel. The proc and clientData identify which close callback to remove; Tcl_Delete-
CloseHandler does nothing if its proc and clientData arguments do not match the proc and clientData for a close handler for channel.
SEE ALSO close(1T), Tcl_Close(3TCL), Tcl_UnregisterChannel(3TCL)KEYWORDS
callback, channel closing
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Availability | SUNWTcl |
+--------------------+-----------------+
|Interface Stability | Uncommitted |
+--------------------+-----------------+
NOTES
Source for Tcl is available on http://opensolaris.org.
Tcl 7.5 Tcl_CreateCloseHandler(3TCL)
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Tcl_CreateChannelHandler(3) Tcl Library Procedures Tcl_CreateChannelHandler(3)__________________________________________________________________________________________________________________________________________________NAME
Tcl_CreateChannelHandler, Tcl_DeleteChannelHandler - call a procedure when a channel becomes readable or writable
SYNOPSIS
#include <tcl.h>
void
Tcl_CreateChannelHandler(channel, mask, proc, clientData)
void
Tcl_DeleteChannelHandler(channel, proc, clientData)
ARGUMENTS
Tcl_Channel channel (in) Tcl channel such as returned by Tcl_CreateChannel.
int mask (in) Conditions under which proc should be called: OR-ed combination of TCL_READABLE, TCL_WRITABLE and
TCL_EXCEPTION. Specify a zero value to temporarily disable an existing handler.
Tcl_FileProc *proc (in) Procedure to invoke whenever the channel indicated by channel meets the conditions specified by
mask.
ClientData clientData (in) Arbitrary one-word value to pass to proc.
_________________________________________________________________DESCRIPTION
Tcl_CreateChannelHandler arranges for proc to be called in the future whenever input or output becomes possible on the channel identified
by channel, or whenever an exceptional condition exists for channel. The conditions of interest under which proc will be invoked are speci-
fied by the mask argument. See the manual entry for fileevent for a precise description of what it means for a channel to be readable or
writable. Proc must conform to the following prototype:
typedef void Tcl_ChannelProc(
ClientData clientData,
int mask);
The clientData argument is the same as the value passed to Tcl_CreateChannelHandler when the handler was created. Typically, clientData
points to a data structure containing application-specific information about the channel. Mask is an integer mask indicating which of the
requested conditions actually exists for the channel; it will contain a subset of the bits from the mask argument to Tcl_CreateChannelHan-
dler when the handler was created.
Each channel handler is identified by a unique combination of channel, proc and clientData. There may be many handlers for a given channel
as long as they do not have the same channel, proc, and clientData. If Tcl_CreateChannelHandler is invoked when there is already a handler
for channel, proc, and clientData, then no new handler is created; instead, the mask is changed for the existing handler.
Tcl_DeleteChannelHandler deletes a channel handler identified by channel, proc and clientData; if no such handler exists, the call has no
effect.
Channel handlers are invoked via the Tcl event mechanism, so they are only useful in applications that are event-driven. Note also that
the conditions specified in the mask argument to proc may no longer exist when proc is invoked: for example, if there are two handlers for
TCL_READABLE on the same channel, the first handler could consume all of the available input so that the channel is no longer readable when
the second handler is invoked. For this reason it may be useful to use nonblocking I/O on channels for which there are event handlers.
SEE ALSO Notifier(3), Tcl_CreateChannel(3), Tcl_OpenFileChannel(3), vwait(n).
KEYWORDS
blocking, callback, channel, events, handler, nonblocking.
Tcl 7.5 Tcl_CreateChannelHandler(3)