postscript Error Handling Sequence of events when an error is signaled
Example
The sequence for an error is usually:
- error is triggered by looking up the error name in
errordictand executing this procedure. - the
errordictprocedure callssignalerror, passing it the error name. signalerrortakes snapshots of the stacks, saving the snapshots in$error, and then callsstop.stoppops the exec stack until the nearest enclosing stopped context established by the stopped operator.- if the program has not established its own stopped context to catch the error, it will be caught by an outer-level
stopped { errordict /handleerror get exec } ifwhich was called by the startup code to bracket the whole user program. handleerroruses the information in$errorto print an error report.
