RE: Finding the length of a passed parameter

["York, Albert" <albert.york@xxxxxxxxxxxxxx>]

Thanks Scott. 

As always, you have left a broad swath of enlightenment in your wake. :-)

For reasons I won't go into, I don't want to add a field for length.
However, I can prefix the data with a type code, which will tell me what I
need to know.


Albert York                          



        -----Original Message-----
        From:   Scott Klement [SMTP:klemscot@xxxxxxxxxxxx]
        Sent:   Thursday, September 18, 2003 9:26 AM
        To:     Midrange Systems Technical Discussion
        Subject:        RE: Finding the length of a passed parameter

        >
        > However, I am writing a program which will accept a variable
number of
        > parameters of different length. I can easily find out how many
parameters
        > were passed but I am looking for a way to find out how long each
one is. In
        > my program I can allow for the maximum length and subscript as
needed.
        >

        The programs are, in a way, talking to each other when they send
        parameters.   One program is telling the next program "I'm passing 3
        parameters, and they are (address) (address) (address)"

        Programs don't tell each other the lengths.  They also don't tell
each
        other the data types.   They just give a number of parameters and an
        address in memory.  That's it.

        Therefore there's no way to retrieve the length, aside from having
the
        calling program pass that length as an additional parameter.
That's why
        APIs frequently will have both "data" and "length" parameters.
QCMDEXC
        is a simple example, the first parm is the command, the second is
the
        length.

        Now, IBM could enhance the operating system... perhaps adding a new
        parameter to the call command such as SNDLEN(*YES) to tell the call
to
        send the lengths of each parameter.   But, each program that wanted
to
        use it would have to be changed to specify that SNDLEN(*YES).  It
couldn't
        be changed universally without breaking backwards compatibility.
        Of course, all this would really do is add "hidden" parameters that
        contain the length of each of the "visible" parameters.

        Since you'd have to change the calling program anyway, you may as
well
        just add parameters containing the lengths.   That way, you can
solve
        your problems today.

        Hope that helps you understand (even if it doesn't solve your
problem)

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