Caché ObjectScript Reference - InterSystems Documentation

Caché ObjectScript Special Variables• Magnetic Tape I/O in Caché I/O Device Guide• Sequential File I/O in Caché I/O Device Guide• The Spool Device in Caché I/O Device Guide$ZCHILDContains the ID of the last child process.$ZCHILD$ZCDescription$ZCHILD contains the ID of the last child process that the current process created with theJOB command. If your process hasn't used JOB to create a child process, $ZCHILD returns0 (zero).In MSM language mode, the $ZC special variable (spelled as shown) has a different use. Itis used for determining end-of-file in sequential file reads.This special variable cannot be modified using the SET command. Attempting to do so resultsin a error.Notes$ZCHILD and the Successful Starting of Jobs$ZCHILD being set does not mean that the job was successfully started. It only means thatthe process was created and the parameters were passed successfully.For example, if you use JOB to spawn a routine that does not exist, both $TEST and$ZCHILD report that the JOB command succeeded, although that new job immediately dieswith a error.$ZC in MSM Language ModeMSM language mode supports a special use of the $ZC special variable.If you have set the current language mode to MSM using $ZUTIL(55,8), the $ZC specialvariable is set during sequential file reads. This provides compatibility with the MSM $ZCvariable. (In all other language modes, $ZC is not set during file reads; $ZC is an abbreviationfor $ZCHILD and has a completely different functionality.)466 Caché ObjectScript Reference