The File Control Description (FCD) is a data area which contains information about the file in use.
There are two different formats of the FCD that you can directly code in your application, FCD2 and FCD3 (FCD 1 is obsolete and should never be used in your applications).
FCD2 is not supported on 64-bit COBOL systems. This has the following effects on application conversion:
- Applications that use FCD structures, either through explicit declaration and creation, or by using the syntax CALL
program USING
filename, have to be converted to handle FCD3 when compiled and run as a 64-bit application.
- Applications that use the FCDREG directive need to be aware that various data-items including pointers and record sizes within the FCD have different sizes, and that reference modification of these fields results in different values on a 32-bit environment and a 64-bit one.
- The copybook
xfhfcd.cpy defines an FCD3 unless you specify the NOFCD3 directive. The FCD3 record is directly and unconditionally defined in the file
xfhfcd3.cpy and the FCD2 record is directly and unconditionally defined in the file
xfhfcd2.cpy.
