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Why? catch script ?varName? Here's an example of using catch to implement a version of the info exists command: proc varexists {var} { upvar $var v if [catch {set v}] { return 0 } else Special Variable & Description 1 argc Refers to a number of command-line arguments. 2 argv Refers to the list containing the command-line arguments. 3 argv0 Refers to the file name of http://colinmeldrum.com/tcl-error/tcl-error-stack-trace.html

If the info argument is present, it is used to initialize the -errorinfo return options and the first increment of unwind information will not be added by the Tcl interpreter. The programmer can then decide what to do about those errors and act accordingly, instead of having the whole application come to a halt. Creating Control Structures and Exception Handling The uplevel Command uplevel ?level? If there is an error, default is returned (or the empty string, if default isn't specified). https://www.tcl.tk/man/tcl8.5/tutorial/Tcl36.html

Tcl Catch Example

The mechanism by which these options work is described in more detail below. -options options The value options must be a valid dictionary. DESCRIPTIONThe catch command may be used to prevent errors from aborting command interpretation. Copyright © 1994-1996 Sun Microsystems, Inc.

Feb 7 '10 at 2:59 add a comment| up vote 1 down vote Given your further refinement of your question, the following may work for you: # gets the stack up error (or 1) Error return: the return code of the procedure is 1 (TCL_ERROR). Generates a return exception condition. Tcl Return Error The error stack will also be reachable through info errorstack.

The values of the -errorinfo and -errorcode entries of the most recent error are also available as values of the global variables ::errorInfo and ::errorCode respectively. Tcl Error Handling It defines the number of levels up the stack at which the return code of a command currently being evaluated should be code. The -errorcode return option is intended to hold a machine-readable description of the error in cases where such information is available; see the return manual page for information on the proper look at this site Three other standard exceptions are: The return condition, generated by the return command.

The return code of the return command itself triggers this special handling by procedure invocation. Tcl Proc Return Value Otherwise it is 1. The alarm Command alarm seconds The Extended Tcl alarm command arranges for the kernel to send your process a SIGALRM (signal 14) in seconds seconds (this is a floating point value, Thanks for your generous input! –ls.

Tcl Error Handling

For example, if an open call returns an error, the user could be prompted to provide another file name. http://stackoverflow.com/questions/2193731/stack-trace-info-in-errorinfo-in-tcl Not the answer you're looking for? Tcl Catch Example The error Command error message ?info? ?code? Tcl Error Command Add a language to a polyglot Error in shell bracket test when string is a left-parenthesis Why are there no toilets on the starship 'Exciting Undertaking'?

error $errMsg $savedInfo When working with Tcl 8.5 or later, the following code should be used instead: catch {...} errMsg options ... navigate here signal is the signal number or name of the signal you want to send (SIGTERM is the default), and idlist is a list of process id's. The self class/self method command when run in the right stack scope will be useful, as will info class definition and/or info object definition: self class and self method say what Edited to add more details say I have following code: proc test1 {} { set list {1 2 3 4 5} set sum 0 foreach el $list { if {[catch {set Tcl Errorinfo

Eating Skittles Like a Normal Person Why am I getting different p-values out of a z-table than the ones described in my textbook? If no error occurs, catch returns 0. A classic use of unwindProtect is to close files even if an error occurs in processing: foreach file $filelist { if [catch {open $file} result] { puts stderr "Warning: $result" } Check This Out The break condition, generated by the break command.

Making a Planet Seem Uninhabitable A pilot's messages A riddle of honour What are some counter-intuitive results in mathematics that involve only finite objects? Tcl Catch Exec Message is a string that is returned to the application to indicate what went wrong. Tcl also defines four exceptional return codes: 1 (TCL_ERROR), 2 (TCL_RETURN), 3 (TCL_BREAK), and 4 (TCL_CONTINUE).

While the stack trace is useful during debugging, it's probably not desirable for a production program.

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. arg ... The value of the -errorcode entry is additional information about the error stored as a list. Invalid Command Name Tcl command is executed in the global context; an occurrence of the string %S in command will be replaced with the signal name (use %% to get a percent sign); get, which

When the return code from evaluation of script is TCL_ERROR, four additional entries are defined in the dictionary of return options stored in optionsVarName: -errorinfo, -errorcode, -errorline, and -errorstack. EXAMPLESThe catch command may be used in an if to branch based on the success of a script. Tcl version #!/usr/bin/tclsh puts $tcl_version When you run the program, you will get a similar output as shown below − 8.6 Tcl Environment Path #!/usr/bin/tclsh puts $env(PATH) When you run the http://colinmeldrum.com/tcl-error/tcl-error-f5.html See page 122 in Ousterhout.

The return value of catch is the status return of the Tcl interpreter after it executes script If there are no errors in script, this value is 0. You can program with Unix signals via the Extended Tcl signal command. How can I display this error info using catch? value The string value will be the value returned by this proc. errorInfo errorInfo is a global variable that contains the error information from commands that have failed.