Re: Varying fields as parameters on procedure calls.

On 2015-04-10 19:13, Alan Campin wrote:

Just a quick question. I was reading on article on the web and it stated
that if I had a varying fields that what would get passed by VALUE would be
just the first two digits for the length and the actual length of the data.

It has always been my understanding if I had field that was 64K varying and
I passed it as a parameter that the 64K plus two (or four) bytes for the
length is what would be passed even I only had say 10 bytes of data.

You're right that for a parameter passed by value, the entire 64K + 2 or 4 bytes would be passed, even though the called procedure would normally only see the length meaningful length.

Ted Holt wrote an article comparing the performance of the various passing modes, and he came to the conclusion that there was a strong case for avoiding pass-by-value completely.
http://www.itjungle.com/fhg/fhg062007-story01.html

Here's an tech tip I wrote a long time ago about CONST vs VALUE for string parameters. (At the top it says the author is Guest.Visitor, but at the end it credits me.)
http://www.mcpressonline.com/tips-techniques/rpg/techtip-string-parameters-is-value-or-const-better.html