Import Tcl-core 8.6.6 (as of svn r86089)

doc/exit.n

@@ -0,0 +1,51 @@
+'\"
+'\" Copyright (c) 1993 The Regents of the University of California.
+'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
+'\"
+'\" See the file "license.terms" for information on usage and redistribution
+'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+'\" 
+.TH exit n "" Tcl "Tcl Built-In Commands"
+.so man.macros
+.BS
+'\" Note:  do not modify the .SH NAME line immediately below!
+.SH NAME
+exit \- End the application
+.SH SYNOPSIS
+\fBexit \fR?\fIreturnCode\fR?
+.BE
+
+.SH DESCRIPTION
+.PP
+Terminate the process, returning \fIreturnCode\fR to the
+system as the exit status.
+If \fIreturnCode\fR is not specified then it defaults
+to 0.
+.SH EXAMPLE
+.PP
+Since non-zero exit codes are usually interpreted as error cases by
+the calling process, the \fBexit\fR command is an important part of
+signaling that something fatal has gone wrong. This code fragment is
+useful in scripts to act as a general problem trap:
+.PP
+.CS
+proc main {} {
+    # ... put the real main code in here ...
+}
+
+if {[catch {main} msg options]} {
+    puts stderr "unexpected script error: $msg"
+    if {[info exists env(DEBUG)]} {
+        puts stderr "---- BEGIN TRACE ----"
+        puts stderr [dict get $options -errorinfo]
+        puts stderr "---- END TRACE ----"
+    }
+
+    # Reserve code 1 for "expected" error exits...
+    \fBexit\fR 2
+}
+.CE
+.SH "SEE ALSO"
+exec(n)
+.SH KEYWORDS
+abort, exit, process