14 Aug 94, Rob Landley writes to Jon Guthrie:

 >> I suspect that, as a dos programmer, you'll be more interested in
 >> text-mode, at least for a while.

 > Not necessarily.  I have nothing against the GUI concept.  Just windows.

Still, it's less to learn, at least in the beginning.  I STILL do more
text-mode stuff than PM stuff.  (Although I AM doing more PM stuff lately.)

 >> Why do you want to know about the API calls?  What int21 calls do you
 >> commonly use under DOS?  Most of the API is virtualized by the C
 >> library.

 > I know that.  I need to learn the new C library for OS/2, to do things
 > like semaphores, waiting without using time slices, creating new
 > threads, getting a directory with all the new extended info and long
 > names...  Text mode color changing and cursor movement, and of course
 > the PM graphics library...

Waiting without using time slices is done by designing your program to not
use time slices.  That's what multithreading is all about.  The whole idea
is to NEVER use "busy waiting."  Semaphores are used either to
wait for an event without wasting time or to serialize access to a resource
to avoid race conditions.

To create a thread, use _beginthread.  (Thread creation is really easy. 
It's coordinating between the multiple threads that takes some skill.)

I don't know anything about getting directories.  (Sorry, but I haven't had
a use for it.)  You use long names by using long names.  The thing is, you
have to check and make sure you CAN use long names, first.  Otherwise, it
will fail.

Text mode color changing is normally handled through the Vio... calls. 
(You can also use ANSI without any difficulty.)  PM is NOT a "graphics
library," it's a window management library.  For graphics under PM,
one uses the Gpi facility.

REAL WORLD PROGRAMMING FOR OS/2 2.1 seems to have a lot of information on
the PM/GPI issues.  I learned about the issues of interest to people
writing multithreaded programs (race conditions and deadlocks, to name two)
some time ago.  (I seem to recall 1984, or thereabouts.)  That means that
I'm not someone you should ask about how to learn that stuff.

Frankly, the two best books for what you want to know are out of print.

- Jon

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