how to use a file in called program?

Prasanna Srinivas D · New User Joined: 12 Oct 2007 Posts: 9 Location: chennai

hi,

I have to open a file in the main program which calls other program modules. The modules also use the file (read and write). The main program is also responsible for closing the file.

1> Is write possible in the module program if i pass the buffer descrtiptor to the module from the main program?

eg. file section.
fd file1
01 fs-buffer
.....
.....
procedure division.
call module1 using fs-buffer

2> How is read possible in the module program? since read uses the file name itself, is there any way to pass the file name to the module

dbzTHEdinosauer · Posted: Sat Oct 27, 2007 4:20 pm

no, cobol is rather explicit about which module can perform i/O. Which ever module contains the FD, that module, and only that module, can execute i/o against the FD.

Suggest that you remove the FD from the main module, write a new module (an i/o module) that can be called from anyone to perform the i/O functions. The way you have it set-up, a submodule must return to the main module to get the next or write/rewrite and then immediately be called again by the main-module. That means a lot of decision making in the main as well as the sub-module.

removing i/o to a sub-module allows a programmer to design a flexible run-unit. any module needing another record or wanting to update the file can perform an 'in-line call' to the i/o module.

In addition, if the data was formerly in a qsam file, it could be changed very easily to a vsam or db2 by only having to modify 1 i/o module.

Prasanna Srinivas D · New User Joined: 12 Oct 2007 Posts: 9 Location: chennai

thank you for the technique... this is much better...