Caché ObjectScript Reference - InterSystems Documentation

Caché ObjectScript Special Variables$ETRAP Value is a Line of ObjectScript CodeBecause the string value of $ETRAP is executable Caché ObjectScript commands, the lengthof the string cannot be longer than the maximum length of a Caché ObjectScript routine line.See Using Caché ObjectScript for more information.$ETRAP and Error HandlingThe $ETRAP special variable is one of many Caché ObjectScript language features thatenable you to control the handling and logging of errors that occur in your applications.$ETRAP in particular plays an important role in controlling the flow of execution after anerror occurs. See Error Handling in Using Caché ObjectScript for more information abouterror handling.When setting $ETRAP to execute an error handler (for example, with a GOTO command)you can specify the error handler as tag (a label in the current routine), ^routine (the beginningof a specified external routine), or tag^routine (a specified label in a specified external routine).$ETRAP supports tag+offset in some contexts (but not in procedures). This optional +offsetis an integer specifying the number of lines to offset from tag. InterSystems recommendsthat you avoid the use of a line offset when specifying an error handler location.When you set an error handler using $ZTRAP, this handler takes precedence over anyexisting $ETRAP error handler. Caché implicitly performs a NEW $ETRAP command andsets $ETRAP to the null string ("").See Also• NEW command• SET command• $ECODE special variable• $ZEOF special variable• $ZTRAP special variable• Error Handling in Using Caché ObjectScript428 Caché ObjectScript Reference