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Assume you need to call mycmd, and it might raise errors. # Tcl 8.6 try mycmd on error {} {} # Tcl 8.4 or later catch mycmd This invocation quietly intercepts error-handling tcl share|improve this question asked May 13 '15 at 10:53 Ashot 4,34173071 add a comment| 1 Answer 1 active oldest votes up vote 3 down vote accepted The short answer If the info argument is provided and is non-empty, it is used to initialize the global variable errorInfo. The errorInfo variable[edit] This global variable provided by Tcl contains the last error message and the traceback of the last error. have a peek here

Not the answer you're looking for? You can turn off the stack trace with the -n argument to the megatcl (or Extended Tcl) interpreter: $ megatcl -n -c "while 1 {if 1 {set foo}}" Error: can't read Otherwise it is 1. Here's a very simple one: proc tracer args {puts $args} Now we instruct the interpreter to trace enter and leave of fac: trace add execution fac {enter leave} tracer Let's test http://wiki.tcl.tk/error

Tcl Error Handling

The errdefault Command errdefault code ?default? Also cacheing in objects and multiple catch clauses example.Preparing data through a little bit of PerlSegmentation Fault, Segmentation Violation, Bus Error, Stack Smashing Command line and file handling in CHandling JSON Why were weapons like Mandrakes and Acromantula, which kill indiscriminately, used in the Battle of Hogwarts? Here's the program above, enhanced to catch any errors:
puts -nonewline "please enter a number: "
flush stdout
gets stdin value
if {[catch {set doubled [expr

In C, you would have received a NULL pointer, and without checking that, Segmentation Fault would be right around the corner. as a Tcl script in the calling context. If not, the error is placed in varName. Tcl Catch Example Signal names can be given as either SIGINT or INT.

In other words, the command containing the error command will not appear in the stack trace; in its place will be info. Since the console is a Tk text widget, you can use all text widget commands and options on it (for example, changing colors, bindings...). error message ?info? ?code? my company If however you feed this file directly to a tclsh, that fact is detected, and the "e.g." calls are executed.

An example is shown below − #!/usr/bin/tclsh catch {set file [open myNonexistingfile.txt]} result puts "ErrorMsg: $result" puts "ErrorCode: $errorCode" puts "ErrorInfo:\n$errorInfo\n" When the above code is executed, it produces the following Tcl Return Error catch { timeout 30 { lassign [server_open $host $port] read write } } Keith WaclenaThe University of Chicago Library This page last updated: Thu Aug 25 13:28:18 CDT 1994 This page catch script ?varName? This is perfectly acceptable if the error isn't important, e.g.

Tcl Error Python

try mycmd on error msg {puts stderr "There was a problem: $msg"} if {[catch mycmd msg]} { puts stderr "There was a problem: $msg" } You might want to take some http://www.astro.princeton.edu/~rhl/Tcl-Tk_docs/tcl/error.n.html catch returns a different non-zero numeric code for each of them. Tcl Error Handling While the stack trace is useful during debugging, it's probably not desirable for a production program. Tcl Error Code Why are there no toilets on the starship 'Exciting Undertaking'?

Unix Signals Unix signals are similar to Tcl exceptions, in that they are received asynchronously and can be trapped or allowed to have their default behavior. http://colinmeldrum.com/tcl-error/tcl-error-out.html The more complete answer is to look at the catch and the return manual pages and make use of the -optionsVarName parameter to the catch statement to collect the more detailed See the try command. Now testing: % hello Hi! Tcl Throw Error

proc myset {var value} { uplevel set $var $value } uplevel is used to create new control structures; most Tcl commands that take a Tcl scipt as an argument need to If level is given, it specifies the context in which to execute arg ... All Rights Reserved. http://colinmeldrum.com/tcl-error/tcl-print-error-message.html The console is normally hidden, but can be brought up with the command console show You can also use the partially documented "console" command. "console eval script" evals the given script

A Tcl proc can also generate an error status condition. Tcl Warning How to properly localize numbers? Text is available under the Creative Commons Attribution-ShareAlike License.; additional terms may apply.

share|improve this answer answered Dec 29 '14 at 9:02 timrau 17.6k32553 Wo, Ok, thanks. –baoqger Dec 29 '14 at 9:03 add a comment| up vote 0 down vote How

When tclsh is called with no arguments, it starts in an interactive mode and displays a "%" prompt. If supplied, info is used to seed the errorInfo value, and code becomes the errorCode, which is otherwise NONE.error is short for return -level 0 -code error, which is not the You might think that the solution is to use file exists first, but open can fail for many other reasons (improper permissions, etc). Errorinfo Tcl You may want to be sure to be able to perform some cleanup actions upon receipt of these signals; assuming you have a proc called cleanup that does what's necessary, you

Hot Network Questions Most useful knowledge from the 30's to understand current state of computers & networking? set remo [socket localhost 3456] fileevent $remo readable "puts \[gets $remo\]" proc r args {puts $::remo [join $args]; flush $::remo} puts "remote connection ready - use r to talk" Now from such as glob -nocomplain instead of just glob, or in this case file delete file1.txt as suggested by timrau. this contact form Note that unwindProtect doesn't catch the error, it passes it on after executing protected.