Re: DoW (WAS DoU...)

[John Hall <jhall@xxxxxxxxxxx>]

If I was writing this function in c I would simply pass the file handle
as one of the parameters.  My main routine would handle the file open
and close.  There would be no issue as to activation groups, static
variables etc.   I would use the same routine even when the file was
opened more than once (update, read).  How would I accomplish the same
thing in RPGIV.  

Coordinating file access and control between a service program and a
main program adds a level of complexity which cannot improve program
reliability or maintainability.  There are constraints and requirements
placed on the programmer which, at the current time, the 400 development
environment/compilers cannot validate.  If the variable CUST_FILE_OPEN
is supposed to indicate whether or not the file is open but I neglect to
use it or reset it in my main program the compiler will not clearly
indicate this.  It may or may not place a warning message in the compile
about unused variables but when using externally described files you
could have hundreds of those.

This seems to be a major hurdle to writing a library of universal access
routines.  

John Hall
Home Sales Co.

paul cunnane wrote:
> 
> > Someone did ask me a question off-line, where is my file being declared?
> Well,
> > it's being declared in my main program, which brings up the question.
> When I
> > move this function to it's own source file and compile it, I'm going to
> have
> > to declare the file spec in the new source file, right?
> 
> Yup.  And add the USROPN keyword, and open it on the first call to the
> procedure.  There was a debate a while back as to whether %OPEN or a static
> variable was the better approach to determining whether the file has been
> opened yet.  The other burning question is whether the add a cleanup
> procedure to close the file, or to allow it to be closed when the activation
> group ends.
> 
> --
> Paul
>
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