Changes Affecting Version 4.0

Two compilation switches provide compatibility with Version 4.0:

`-C40`	Causes the compiler to generate code according to the rules used by Version 4.0.
`-Z40`	Creates object code that can be run with a Version 4.0 runtime.

The following paragraphs describe changes that can affect programs originally written with ACUCOBOL-GT Version 4.0.

The compiler option -Zx (while still supported) has been replaced with -Fx. Both options cause the compiler to generate XFD files in a new format (XFD Version 4). Version 4 XFD files include a list of all of the fields contained in a file's record description, including group items and REDEFINES items. Items that are excluded from use by the rules of XFD generation are marked with a condition number of 999. Versions of Acu4GL and alfred prior to Version 4.1 require the old format of XFD files. If you want to generate XFDs in the old format, use the new compiler option -Fx3 or use -Z40.
The compiler option -Za now causes the compiler to test table indexes against the upper bound of the current table size when you compile for Version 2.4 or later semantics. Thus, if you have an OCCURS DEPENDING ON table that could hold 20 elements physically, but whose current size is 10 elements, the runtime will produce an error if you access elements 11--20 when compiling with -Za.
Compiling for Version 2.3 or earlier (-C23) causes the compiler to test against the physical upper bound.