diff options
Diffstat (limited to 'doc/after.n')
| -rw-r--r-- | doc/after.n | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/doc/after.n b/doc/after.n index 2a5d005..e61bb88 100644 --- a/doc/after.n +++ b/doc/after.n @@ -24,7 +24,6 @@ after \- Execute a command after a time delay .sp \fBafter info \fR?\fIid\fR? .BE - .SH DESCRIPTION .PP This command is used to delay execution of the program or to execute @@ -32,12 +31,14 @@ a command in background sometime in the future. It has several forms, depending on the first argument to the command: .TP \fBafter \fIms\fR +. \fIMs\fR must be an integer giving a time in milliseconds. The command sleeps for \fIms\fR milliseconds and then returns. While the command is sleeping the application does not respond to events. .TP \fBafter \fIms \fR?\fIscript script script ...\fR? +. In this form the command returns immediately, but it arranges for a Tcl command to be executed \fIms\fR milliseconds later as an event handler. @@ -48,11 +49,12 @@ The command will be executed at global level (outside the context of any Tcl procedure). If an error occurs while executing the delayed command then the background error will be reported by the command -registered with \fB interp bgerror\fR. +registered with \fBinterp bgerror\fR. The \fBafter\fR command returns an identifier that can be used to cancel the delayed command using \fBafter cancel\fR. .TP \fBafter cancel \fIid\fR +. Cancels the execution of a delayed command that was previously scheduled. \fIId\fR indicates which command should be canceled; it must have @@ -61,14 +63,16 @@ If the command given by \fIid\fR has already been executed then the \fBafter cancel\fR command has no effect. .TP \fBafter cancel \fIscript script ...\fR +. This command also cancels the execution of a delayed command. The \fIscript\fR arguments are concatenated together with space separators (just as in the \fBconcat\fR command). If there is a pending command that matches the string, it is -cancelled and will never be executed; if no such command is +canceled and will never be executed; if no such command is currently pending then the \fBafter cancel\fR command has no effect. .TP \fBafter idle \fIscript \fR?\fIscript script ...\fR? +. Concatenates the \fIscript\fR arguments together with space separators (just as in the \fBconcat\fR command), and arranges for the resulting script to be evaluated later as an idle callback. @@ -78,9 +82,10 @@ The command returns an identifier that can be used to cancel the delayed command using \fBafter cancel\fR. If an error occurs while executing the script then the background error will be reported by the command -registered with \fB interp bgerror\fR. +registered with \fBinterp bgerror\fR. .TP \fBafter info \fR?\fIid\fR? +. This command returns information about existing event handlers. If no \fIid\fR argument is supplied, the command returns a list of the identifiers for all existing @@ -88,7 +93,7 @@ event handlers created by the \fBafter\fR command for this interpreter. If \fIid\fR is supplied, it specifies an existing handler; \fIid\fR must have been the return value from some previous call -to \fBafter\fR and it must not have triggered yet or been cancelled. +to \fBafter\fR and it must not have triggered yet or been canceled. In this case the command returns a list with two elements. The first element of the list is the script associated with \fIid\fR, and the second element is either @@ -104,14 +109,16 @@ and \fBupdate\fR commands. .SH "EXAMPLES" This defines a command to make Tcl do nothing at all for \fIN\fR seconds: +.PP .CS proc sleep {N} { - \fBafter\fR [expr {int($N * 1000)}] + \fBafter\fR [expr {int($N * 1000)}] } .CE .PP This arranges for the command \fIwake_up\fR to be run in eight hours (providing the event loop is active at that time): +.PP .CS \fBafter\fR [expr {1000 * 60 * 60 * 8}] wake_up .CE @@ -126,17 +133,19 @@ processing steps (arranging for the next step to be done using an already-triggered timer event only when the event queue has been drained) and is useful when you want to ensure that a Tk GUI remains responsive during a slow task. +.PP .CS proc doOneStep {} { - if {[::my_calc::one_step]} { - \fBafter idle\fR [list \fBafter\fR 0 doOneStep] - } + if {[::my_calc::one_step]} { + \fBafter idle\fR [list \fBafter\fR 0 doOneStep] + } } doOneStep .CE - .SH "SEE ALSO" concat(n), interp(n), update(n), vwait(n) - .SH KEYWORDS cancel, delay, idle callback, sleep, time +'\" Local Variables: +'\" mode: nroff +'\" End: |