archie/tcl7.6/doc/Exit.3
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'\"
'\" Copyright (c) 1995-1996 Sun Microsystems, Inc.
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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'\" SCCS: @(#) Exit.3 1.4 96/03/25 20:02:50
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.so man.macros
.TH Tcl_Exit 3 7.5 Tcl "Tcl Library Procedures"
.BS
.SH NAME
Tcl_Exit, Tcl_CreateExitHandler, Tcl_DeleteExitHandler \- end the application (and invoke exit handlers)
.SH SYNOPSIS
.nf
\fB#include <tcl.h>\fR
.sp
\fBTcl_Exit\fR(\fIstatus\fR)
.sp
\fBTcl_CreateExitHandler\fR(\fIproc, clientData\fR)
.sp
\fBTcl_DeleteExitHandler\fR(\fIproc, clientData\fR)
.SH ARGUMENTS
.AS Tcl_ExitProc clientData
.AP int status in
Provides information about why application exited. Exact meaning may
be platform-specific. 0 usually means a normal exit, 1 means that an
error occurred.
.AP Tcl_ExitProc *proc in
Procedure to invoke before exiting application.
.AP ClientData clientData in
Arbitrary one-word value to pass to \fIproc\fR.
.BE
.SH DESCRIPTION
.PP
\fBTcl_Exit\fR is the procedure that is invoked to end a Tcl application.
It is invoked by the \fBexit\fR command, as well as anyplace else that
terminates the application.
No-one should ever invoke the \fBexit\fR procedure directly; always
invoke \fBTcl_Exit\fR instead, so that it can invoke exit handlers.
.PP
\fBTcl_CreateExitHandler\fR arranges for \fIproc\fR to be invoked
by \fBTcl_Exit\fR before it terminates the application.
This provides a hook for cleanup operations such as flushing buffers
and freeing global memory.
\fIProc\fR should have arguments and return value that match
the type \fBTcl_ExitProc\fR:
.CS
typedef void Tcl_ExitProc(ClientData \fIclientData\fR);
.CE
The \fIclientData\fR parameter to \fIproc\fR is a
copy of the \fIclientData\fR argument given to
\fBTcl_CreateExitHandler\fR when the callback
was created. Typically, \fIclientData\fR points to a data
structure containing application-specific information about
what to do in \fIproc\fR.
.PP
\fBTcl_DeleteExitHandler\fR may be called to delete a
previously-created exit handler. It removes the handler
indicated by \fIproc\fR and \fIclientData\fR so that no call
to \fIproc\fR will be made. If no such handler exists then
\fBTcl_DeleteExitHandler\fR does nothing.
.SH KEYWORDS
callback, end application, exit