xcmds

Mark Wieder mwieder at ahsoftware.net
Sun Dec 11 13:15:29 EST 2005


capellan-

Sunday, December 11, 2005, 9:07:14 AM, you wrote:

> i had buy this book written by Gary Bond about xcmd programming:


> Just US$ 1.08 from Hippo Books.
> i receive it next week. :-)

Gary's book was the bible for developing XCMDs, but it won't help much
for runrev external development these days:

1. The interface to external libraries is entirely different. HC
passed and returned a pointer to a structure of parameters; the
runrev/MetaCard engine passes parameters as individual strings and
returns a single parameter.

2. Many of the examples in Gary's book are no longer necessary, as the
functionality has either now become a part of Transcript or the speed
of processing in the engine has now surpassed that of HC to the point
where you don't need the external for speed any more.

3. IIRC the examples use Think C on OS9, and you'd be hard-pressed to
find a copy these days. You can use CodeWarrior, but of course setting
up the projects will be quite different.

4. Again IIRC, most of the examples used Macintosh Toolbox calls which
are only supported on OS9. Of course external libraries probably won't
be cross-platform in any event, but you're going to have to do a lot
of digging to convert the example code into anything useful.

5. A corollary to the above is that many of the "glue" functions deal
with converting between C and Pascal style so that C functions can
talk to the Toolbox routines written with Pascal conventions. These
are no longer necessary unless you're specifically targetting OS9
externals only.

-- 
-Mark Wieder
 mwieder at ahsoftware.net




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