CHKSUB

Not everything is automatically checked by the compatibility system. For example, your program might use a package last compiled under the previous revision of the compiler, after a point in the main program by which all subsystems had already been used (and checked). Therefore, nothing would trigger re-checking for the package.

With the #CHKSUB compiler directive, you can force compatibility checking by explicitly encoding your packages with their subsystem revision numbers.

To do this, use the following format:

#CHKSUB subsystem# revisionCode

When a #CHKSUBdirective is encountered, the compiler verifies that revisionCode is the same as the revision code for the specified subsystem# carried by the compiler.

If not, Error 175 is reported, but compilation can be continued. One #CHKSUBdirective is required for each subsystem you desire to check.