Differences between Interactive COBOL 4.xx         (4.00) 10-Oct-2008
and Interactive COBOL 2.xx


1.  ICOBOL 3 had a new .cx format that required that all COBOL
    programs be re-compiled.

    ICOBOL 4 allows both ICOBOL 3 format .cx files and ICOBOL 2
    format .cx files to be run.

    An additional IC2X license option is availble to allow this
    to be done.  This option is especially useful for those
    who want to move forward with logging, thinclient support, etc.
    but cannot or do not want to recompile their programs.

Below apply ONLY if the ICOBOL 2 sources are recompiled under
ICOBOL 4

2.  ICOBOL 3 added many new reserved words for the ICOBOL and
    ICOBOL85 dialects.  Variables with these names must be renamed
    if the programs are recompiled.

3.  The ICOBOL 2 compiler allowed a FROM and a USING clause in the
    SCREEN section and generated code as if it was a FROM and a TO
    clause.  This case is now an error.  It must be re-coded if the
    program is recompiled.

4.  Items with USAGE INDEX require 4-bytes of storage.  In ICOBOL 2
    these items required only 2-bytes.  If USAGE INDEX items have been
    included in data files, these files will have to be reorganized to
    allow for 4 rather than 2 bytes for each USAGE INDEX item.

5.  The COMPUTE statement no longer truncates immediate results so
    results in COMPUTE statements should be more accurate as required
    by the standard.

6.  ICOBOL 4 handles parameters to builtins differently than
    ICOBOL 2.  Programs should have exception handling for
    builtin calls to detect errors.

7.  Size error conditions for COMP-5 data items are based on the
    allocated storage rather than the number of digits in the item's
    picture.

8.  The ICOBOL 4 compiler will enforce not allowing an OPEN INPUT
    on a file with an ASSIGN TO PRINTER.

    (This option was useful for checking for file existence.)

    A workaround is to have a duplicate file descriptor as
    an ASSIGN TO KEYBOARD with the same record, name, file status
    etc. and use it in the OPEN INPUT.

9.  When doing an increment to a number that overflowed and no
    size condition was set, ICOBOL 2 would internally generate the
    size condition and not do the store (leaving the value unchanged).
    ICOBOL 4 will not check the size condition and will store the
    truncated value.

    Code should be changed to detect the size condition and do a
    CONTINUE, i.e., ON SIZE CONTINUE.

10. In ICOBOL 4, screens do not support embedded control codes
    for positioning as in ICOBOL 2.  Use variable line and
    column phrases.


End of Differences