Compaq COBOL AAQ2G1FTK, Руководство пользователя

Страница: 92 / 620

Developing Compaq COBOL Programs
1.5 Using Program Switches
On OpenVMS, to test the previous program on an OpenVMS Alpha system,
compile and link it and then type the following:
$ DEFINE COB$SWITCHES 12
$ RUN TSW
The output is as follows:
**TEST SWITCHES**
SWITCH 12 IS ON
**END**
♦
To test the previous program on a Tru64 UNIX system, compile and link it and
then type the following:
% setenv COBOL_SWITCHES 12
% tsw
The output is as follows:
**TEST SWITCHES**
SWITCH 12 IS ON
**END**
1.6 Special Information for Year 2000 Programming
Even subsequent to the turn of the millennium, there still exist potential
disruptions in previously problem-free software where there are instances of a
two-digit year field that should be a four-digit field. Programmers need to correct
all such fields, as Compaq cannot prevent problems that originate in application
code.
Two-digit year formats used in controlling fields, or as keys in indexed files,
can cause program logic to become ambiguous. It is a fundamental rule to use
four-digit years instead of two-digit years in areas where sequential operations
are driven from these values or for comparison of these values.
Compaq COBOL provides programmer access to four-digit and two-digit year
formats:
4-digit FUNCTION CURRENT-DATE
4-digit FUNCTION DATE-OF-INTEGER
4-digit FUNCTION DATE-TO-YYYYMMDD
4-digit FUNCTION DAY-OF-INTEGER
4-digit FUNCTION DAY-TO-YYYYDDD
4-digit FUNCTION INTEGER-OF-DATE
4-digit FUNCTION INTEGER-OF-DAY
4-digit FUNCTION TEST-DATE-YYYYMMDD
4-digit FUNCTION TEST-DAY-YYYYDDD
4-digit FUNCTION WHEN-COMPILED
4-digit FUNCTION YEAR-TO-YYYY
2-digit ACCEPT FROM DATE
2-digit ACCEPT FROM DAY
1–62 Developing Compaq COBOL Programs