4.4.2 Pitfalls when Using Condition Traps There are several pitfalls when using conditions: · Remember that some information are saved across the functions. Both the current trapped condition and the settings of the traps. Consequently, you can not set a trap in a procedure level from a lower level. (I.e. calling a subroutine to set a trap is will not work.) · Remember that SIGL is set when trapped by method CALL. This means that whenever a condition might be trapped by CALL, the SIGL will be set to a new value. Consequently, never trust the contents of the SIGL variable for more than one clause at a time. This is very frustrating, but at least it will not happen often. When it do happen, though, you will probably have a hard time debugging it. · Also remember that if you use the PROCEDURE clause in a condition handler called by method CALL, remember to EXPOSE the special variables SIGL if you want to use it inside the condition handler. Else it will be shadowed by the PROCEDURE.