return tcl 7.0
Overview
Return from a procedure
Syntax
return ?-code code? ?-errorinfo info? ?-errorcode code? ?string?
Description
Return immediately from the current procedure (or top-level command or source command), with string as the return value. If string is not specified then an empty string will be returned as result.
Exceptional Returns
In the usual case where the -code option isn't specified the procedure will return normally (its completion code will be TCL_OK). However, the -code option may be used to generate an exceptional return from the procedure. Code may have any of the following values:
| ok
| Normal return: same as if the option is omitted.
|
| error
| Error return: same as if the error command were used to terminate the procedure, except for handling of errorInfo and errorCode variables (see below).
|
| return
| The current procedure will return with a completion code of TCL_RETURN, so that the procedure that invoked it will return also.
|
| break
| The current procedure will return with a completion code of TCL_BREAK, which will terminate the innermost nested loop in the code that invoked the current procedure.
|
| continue
| The current procedure will return with a completion code of TCL_CONTINUE, which will terminate the current iteration of the innermost nested loop in the code that invoked the current procedure.
|
| value
| Value must be an integer; it will be returned as the completion code for the current procedure.
|
The -code option is rarely used. It is provided so that procedures that implement new control structures can reflect exceptional conditions back to their callers.
Two additional options, -errorinfo and -errorcode, may be used to provide additional information during error returns. These options are ignored unless code is error.
The -errorinfo option specifies an initial stack trace for the errorInfo variable; if it is not specified then the stack trace left in errorInfo will include the call to the procedure and higher levels on the stack but it will not include any information about the context of the error within the procedure. Typically the info value is supplied from the value left in errorInfo after a catch command trapped an error within the procedure.
If the -errorcodeoption is specified then code provides a value for the errorCode variable. If the option is not specified then errorCode will default to NONE.
Keywords
break, continue, error, procedure, return
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