Re: Member Names

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

P
Hello Buck,
You wrote (in response to Joel):
>Good point.  The APIs are generally very fast compared to system utilities.
>I haven't personally benchmarked QULSMBR vs. DSPFD though.

First major performance benefit is that creating a database file is a lot 
slower than 
creating a user space (DB files are complex objects made up of many parts, user 
spaces 
are relatively simple).  Also, I/O to a DB file is going through the various DB 
routines 
which will be slower than simply copying data to a space location.

>The API has one big advantage over DSPFD OUTFILE() - the API's returned data
>format is guaranteed not to change.  The outfile offers no such guarantee.
>With the new database features that have arrived (more on the way!) this
>should be a consideration.

I thought some clarification was in order.  Neither API formats nor outfiles 
are immune 
from change.  In both cases Rochester can add extra fields.  Outfiles are 
(supposed to 
be) created with LVLCHK(*NO) and additional fields are (supposed to be) added 
at the end 
thus protecting a program from release changes.

APIs have similar rules in that new fields can be added by using existing 
reserved space 
or by extending the format.  Even though the format may have increased your 
program will 
be protected if you also follow the rules.  Rule 1 is to use the header field 
that holds 
the size of a list entry to navigate the data (Don't under any circumstances do 
the 
C-language trick of declaring a pointer of type List_Entry_t and simply 
increment it.  
That code is guarenteed to break on later releases.)

If the rules are followed then a single format can be enhanced without damage 
to 
existing programs.  Someone should explain that to the NetServer developers.  
They 
created formats 0101 and 0201 at VRM440 simply to add new fields (4 new fields 
and a 
variable structure in the case of 0101 and a single new field in the case of 
0201). Doh!  
All they had to do was extend the existing 0100 and 0200 formats and magic 
happens.  
Talk about making life difficult!  Has anyone worked out that I'm really not 
impressed 
by the NetServer developers :)

Regards,
Simon Coulter.

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