diff options
Diffstat (limited to 'doc/Exit.3')
| -rw-r--r-- | doc/Exit.3 | 51 |
1 files changed, 30 insertions, 21 deletions
@@ -4,13 +4,11 @@ '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" -'\" RCS: @(#) $Id: Exit.3,v 1.4 2000/07/24 00:03:02 jenglish Exp $ -'\" +.TH Tcl_Exit 3 8.5 Tcl "Tcl Library Procedures" .so man.macros -.TH Tcl_Exit 3 8.1 Tcl "Tcl Library Procedures" .BS .SH NAME -Tcl_Exit, Tcl_Finalize, Tcl_CreateExitHandler, Tcl_DeleteExitHandler, Tcl_ExitThread, Tcl_FinalizeThread, Tcl_CreateThreadExitHandler, Tcl_DeleteThreadExitHandler \- end the application or thread (and invoke exit handlers) +Tcl_Exit, Tcl_Finalize, Tcl_CreateExitHandler, Tcl_DeleteExitHandler, Tcl_ExitThread, Tcl_FinalizeThread, Tcl_CreateThreadExitHandler, Tcl_DeleteThreadExitHandler, Tcl_SetExitProc \- end the application or thread (and invoke exit handlers) .SH SYNOPSIS .nf \fB#include <tcl.h>\fR @@ -30,6 +28,9 @@ Tcl_Exit, Tcl_Finalize, Tcl_CreateExitHandler, Tcl_DeleteExitHandler, Tcl_ExitTh \fBTcl_CreateThreadExitHandler\fR(\fIproc, clientData\fR) .sp \fBTcl_DeleteThreadExitHandler\fR(\fIproc, clientData\fR) +.sp +Tcl_ExitProc * +\fBTcl_SetExitProc\fR(\fIproc\fR) .SH ARGUMENTS .AS Tcl_ExitProc clientData .AP int status in @@ -38,7 +39,9 @@ Exact meaning may be platform-specific. 0 usually means a normal exit, any nonzero value usually means that an error occurred. .AP Tcl_ExitProc *proc in -Procedure to invoke before exiting application. +Procedure to invoke before exiting application, or (for +\fBTcl_SetExitProc\fR) NULL to uninstall the current application exit +procedure. .AP ClientData clientData in Arbitrary one-word value to pass to \fIproc\fR. .BE @@ -59,28 +62,26 @@ otherwise causes the application to terminate without calling \fBTcl_Exit\fR, the exit handlers will not be run. \fBTcl_Exit\fR internally invokes the \fBexit\fR system call, thus it never returns control to its caller. +If an application exit handler has been installed (see +\fBTcl_SetExitProc\fR), that handler is invoked with an argument +consisting of the exit status (cast to ClientData); the application +exit handler should not return control to Tcl. .PP \fBTcl_Finalize\fR is similar to \fBTcl_Exit\fR except that it does not exit from the current process. It is useful for cleaning up when a process is finished using \fBTcl\fR but wishes to continue executing, and when \fBTcl\fR is used in a dynamically loaded extension that is about to be unloaded. -On some systems \fBTcl\fR is automatically notified when it is being -unloaded, and it calls \fBTcl_Finalize\fR internally; on these systems it -not necessary for the caller to explicitly call \fBTcl_Finalize\fR. -However, to ensure portability, your code should always invoke -\fBTcl_Finalize\fR when \fBTcl\fR is being unloaded, to ensure that the -code will work on all platforms. \fBTcl_Finalize\fR can be safely called +Your code should always invoke \fBTcl_Finalize\fR when \fBTcl\fR is being +unloaded, to ensure proper cleanup. \fBTcl_Finalize\fR can be safely called more than once. .PP -.VS \fBTcl_ExitThread\fR is used to terminate the current thread and invoke per-thread exit handlers. This finalization is done by \fBTcl_FinalizeThread\fR, which you can call if you just want to clean up per-thread state and invoke the thread exit handlers. \fBTcl_Finalize\fR calls \fBTcl_FinalizeThread\fR for the current thread automatically. -.VE .PP \fBTcl_CreateExitHandler\fR arranges for \fIproc\fR to be invoked by \fBTcl_Finalize\fR and \fBTcl_Exit\fR. @@ -89,9 +90,12 @@ by \fBTcl_FinalizeThread\fR and \fBTcl_ExitThread\fR. This provides a hook for cleanup operations such as flushing buffers and freeing global memory. \fIProc\fR should match the type \fBTcl_ExitProc\fR: +.PP .CS -typedef void Tcl_ExitProc(ClientData \fIclientData\fR); +typedef void \fBTcl_ExitProc\fR( + ClientData \fIclientData\fR); .CE +.PP The \fIclientData\fR parameter to \fIproc\fR is a copy of the \fIclientData\fR argument given to \fBTcl_CreateExitHandler\fR or \fBTcl_CreateThreadExitHandler\fR when @@ -107,8 +111,6 @@ 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 or \fBTcl_DeleteThreadExitHandler\fR does nothing. .PP -.VS -.PP \fBTcl_Finalize\fR and \fBTcl_Exit\fR execute all registered exit handlers, in reverse order from the order in which they were registered. This matches the natural order in which extensions are loaded and unloaded; @@ -117,15 +119,22 @@ unloads \fBB\fR before it itself is unloaded. If extension \fBA\fR registers its exit handlers before loading extension \fBB\fR, this ensures that any exit handlers for \fBB\fR will be executed before the exit handlers for \fBA\fR. -.VE -.VS .PP \fBTcl_Finalize\fR and \fBTcl_Exit\fR call \fBTcl_FinalizeThread\fR and the thread exit handlers \fIafter\fR the process-wide exit handlers. This is because thread finalization shuts down the I/O channel system, so any attempt at I/O by the global exit handlers will vanish into the bitbucket. -.VE - +.PP +\fBTcl_SetExitProc\fR installs an application exit handler, returning +the previously-installed application exit handler or NULL if no +application handler was installed. If an application exit handler is +installed, that exit handler takes over complete responsibility for +finalization of Tcl's subsystems via \fBTcl_Finalize\fR at an +appropriate time. The argument passed to \fIproc\fR when it is +invoked will be the exit status code (as passed to \fBTcl_Exit\fR) +cast to a ClientData value. +.SH "SEE ALSO" +exit(n) .SH KEYWORDS -callback, cleanup, dynamic loading, end application, exit, unloading, thread +abort, callback, cleanup, dynamic loading, end application, exit, unloading, thread |