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The -errorinfo return option of an interpreter is used to accumulate a stack trace of what was in progress when an error occurred; as nested commands unwind, the Tcl interpreter adds If the code argument is not present, then errorCode is automatically reset to ``NONE'' by the Tcl interpreter as part of processing the error generated by the command. This feature is most useful in conjunction with the catch command: if a caught error cannot be handled successfully, info can be used to return a stack trace reflecting the original error message ?info? ?code? http://colinmeldrum.com/tcl-error/tcl-error-f5.html

If no error occurred, var is set to contain the result of executing the script. arg ... proc errdefault {code {default ""}} { if [catch {uplevel 1 $code} result] { return $default } else { return $result } } set fp [errdefault {open $file r} stdin] The unwindProtect A riddle of honour How many dimensions does electricity have?

Tcl Error Handling

It is possible to "catch" errors and exceptions with the catch command, which runs some code, and catches any errors that code happens to generate. Similarly, it is possible to catch the error generated by Tcl. If an error occurs deep within several levels of procedure invocations, the stack trace can be very long.

If the code argument is not present, then errorCode is automatically reset to ``NONE'' by the Tcl interpreter as part of processing the error generated by the command. When you start up a Tcl interpreter, get a prompt, and type in commands to Tcl, this is called interactive mode. Synopsis edit error message ?info? ?code? Tcl Return Error error $errMsg $savedInfo If the code argument is present, then its value is stored in the errorCode global variable.

set foo Error: can't read "foo": no such variable The Stack Trace When not running interactively, the Tcl interpreter generates a stack trace upon receipt of an error. Tcl Error Python EXAMPLE Generate an error if a basic mathematical operation fails: if {1+2 != 3} { error "something is very wrong with addition" } SEE ALSO catch, return, tclvars KEYWORDS error, errorCode, 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 https://www.tcl.tk/man/tcl8.4/TclCmd/error.htm This page is intended to provide some assistance in those cases.From http://www.psg.com/~joem/tcl/faq.html#SectionD I start with these questions and answers:"not found" or "Command not found"This error message comes from your shell, not

So in C, you have to add checks for everything that might go wrong; in Tcl, you only need to treat errors if you can express it better than Tcl already Tcl Throw Error Three other standard exceptions are: The return condition, generated by the return command. 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 wiki.tcl.tk errorCode Updated 2016-05-22 00:11:21 by pooryorick ▲ $errorCode, a variable managed by Tcl, contains the value of the -errorcode entry in the options dictionary that describes the last error encountered.

Tcl Error Python

wiki.tcl.tk error Updated 2016-10-02 07:45:53 by dkf ▲ error, a built-in Tcl command, triggers an error state. news The catch Command catch body ?var? Tcl Error Handling as a Tcl script in the calling context. Tcl Error Code Getting Tcl/Tk Getting help Learning Tcl Tcl Dev Xchange About the Wiki Community Advocacy Conferences Chat, news, lists History Humor People Tcl websites Reference Companies Getting help Online books Online tutorials

Evaluates and executes script. navigate here errorInfo is used to accumulate a stack trace of what was in progress when an error occurred; as nested commands unwind, the Tcl interpreter adds information to errorInfo. Does casting pass without a trace prevent other verbal component spells? Many Unix systems are limited to 32 characters (including the #!) in this regard. Tcl Warning

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 And still somehow Zen buddhistic, if you deliberately use a non-existing command, and it does just the right thing... (Kevin Kenny introduced this trick in Tricky catch).In some cases, stack traces The action argument can be one of: default, which specifies the OS's default action for that signal; ignore, which causes the signal to be ignored; error, which causes the signal to Check This Out An example for simple error handling is shown below − #!/usr/bin/tclsh proc Div {a b} { if {$b == 0} { error "Error generated by error" "Info String for error" 401

Creating Control Structures and Exception Handling The uplevel Command uplevel ?level? Tcl Catch Example Incomplete and subject to change at short notice, but something is better than nothing. :-)trythrowreturnArts and crafts of Tcl-Tk programmingCategory Command HomeRecent changesHelpWhoAmI/LogoutCreate new pageRandom pagePrevious pageNext pageAdd commentsEditHistoryEdit summaryReferences Page For instance,set fp [open foo.bar]leads to the errorcouldn't open "foo.bar": no such file or directorywhich tells it pretty well, and does not terminate the application if it has an event loop

See the question "How do I make my script executable regardless of the location of tclsh?" for an example of how to do this.invalid command name "}"You have probably commented out

Getting Tcl/Tk Getting help Learning Tcl Tcl Dev Xchange About the Wiki Community Advocacy Conferences Chat, news, lists History Humor People Tcl websites Reference Companies Getting help Online books Online tutorials idlist The Extended Tcl kill command allows you to send Unix signals to other processes (including yourself). Copyright © 1994-1996 Sun Microsystems, Inc. Errorinfo Tcl If the info argument is provided and is non-empty, it is used to initialize the global variable errorInfo.

The possible arguments are: -code code The next value specifies the return status. more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed Another option is to not specify the path at all. http://colinmeldrum.com/tcl-error/tcl-error-out.html 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.

The standard ARITH, CHILD*, NONE, and POSIX only cover a fraction of all possible error conditions.Tcl syntaxCategory Debugging HomeRecent changesHelpWhoAmI/LogoutCreate new pageRandom pagePrevious pageNext pageAdd commentsEditHistoryEdit summaryReferences Page contents SeeAlso Description Also, sometimes the error msg in question is from the operating system, but it appears as though the error is coming from Tcl. Errors Many Tcl commands generate an error condition when there is a problem (command invoked with invalid arguments, runtime error, etc). The problem in that case is that the caller isn't obeying the interface contract, not that the implementation has gone wrong.RS 2001-11-21: In C, errors are something you loathe and try

Hot Network Questions Most useful knowledge from the 30's to understand current state of computers & networking? in the same manner as upvar. 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 Not the answer you're looking for?

While the stack trace is useful during debugging, it's probably not desirable for a production program. This feature is most useful in conjunction with the catch command: if a caught error cannot be handled successfully, info can be used to return a stack trace reflecting the original The error Command error message ?info? ?code? How can you distinguish them?

If the info argument is present, it is used to initialize errorInfo and the first increment of unwind information will not be added by the Tcl interpreter. In Tcl, they're like "little friends" - helpful (explaining the problem), not messing up everything (as a Segmentation Fault/Bus Error/Divide by Zero would do). The return manual page gives some information on using this. See http://www.psg.com/~joem/tcl/faq.html#CommentStrangeness for more info.Another common cause can be the difference between interactive and command modes for Tcl.

In other words, the command containing the error command will not appear in errorInfo; in its place will be info. See the try command. Making a Planet Seem Uninhabitable more hot questions question feed default about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life alarm can be used in conjunction with signal to generate timeouts.

See Question 12.expected integer but got ...This error occurs when the interpreter was trying to perform some mathematical operation that requires an integer value, but encountered a non-integer value. For convenience, when the evaluation of a command produces an error code, it is also written to $::errorCode.DKF writes in Interrupting loops: The global errorCode variable is probably the best way If varName is supplied, the value returned by script is placed in varName if the script successfully executes. The alarm command returns the number of seconds left in the previous alarm.