The Modify User Hook
Qedit provides a user exit for the Modify commands. To activate this hook, your interface routine or PROCEDURE must store the “plabel” of your modify routine in word 25 of the PROCSPACE (word 26 in FORTRAN). Qedit then sends all Modify operations to this PROCEDURE, which must be structured exactly like a procedure to be called with the Proc command. (See Writing a User Procedure.) To disable the Modify hook, replace the “plabel” word with a zero.
The Set Modify Qzmodify command of Qedit makes use of this user exit to replace the standard Qedit modify routine with a “visual” modify routine.