Re: Passing a Char to a Varchar in RPGLE Procedure Interface -- RPG400-L

Alan,

You'd be correct if this was only being called from RPG. It's actually the prototype in RPG that will do this for you, it will convert to another data type. (And it doesn't have to be by value, it can be either value or CONST reference)

However, that's not at all true when calling from CLLE -- which Mike explicitly said that he wanted.

The CL compiler can't automatically change the data type of the variable, because it doesn't know which data type the RPG procedure is expecting... How could it, if there's no prototype to tell it what the data type should be?!

However, there are ways to do what Mike is looking for, but they are not quite as elegant.

1) You can use operational descriptors to find out the type of data passed. Then, you can treat it accordingly (for example, you could use a pointer to map the parameter to a variable with the appropriate data type.)

2) This is risky, but... a VARYING ("VarChar" is the SQL term) field will have a 2 or 4 byte prefix containing the length. Bytes that make up characters are almost always x'40' or higher. So for parameters with a short max length, if the first byte is < x'40', then it's probably a VARYING parameter, if it's x'40' or higher it's a fixed-length character. Otherwise, it's a varying field.

3) As Joep mentioned, you could have a wrapper. One procedure accepts a fixed-length variable, the other a varying variable. The fixed-length one could call the varying one. That way, the CL can call the fixed-length interface, and RPG can call the varying interface.

On 9/29/2014 12:08 AM, Alan Campin wrote:

The procedure will do it for you. If you are passing by value, when you
pass a char it will automatically map to varchar. The only other thing that
you need to do is to include the option *Trim to cause the value to be
trimmed when it is passed so you get the actual length.

This mechinism would work from CLLE or RPGLE.

On Sun, Sep 28, 2014 at 9:45 PM, Mike Pantzopoulos <
Mike.Pantzopoulos@xxxxxxxxxx> wrote:

I was wondering if there is any way that a Char value can be passed to a
sub-procedure such that it ends up as a Varchar inside the procedure.
In other words, the parameter interface is defined as Varchar(1024), but
the value passed is defined as Char(512). I want to be able to invoke the
procedure from both RPGLE and CLLE, and as CLLE does not have a native
VARCHAR definition I was hoping to be able to get the parameter passing
mechanism to do this on-the-fly.

I know how to create a VARCHAR like value in CL, but don't want fellow
developers to have to go through this pain to use my sub-procedure..

TIA...

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