🚀 go-pugleaf

jmeyers@ecst.csuchico.edu (Jeff Meyers) writes:

>I have written a simple installation program in Turbo Pascal and am having
>trouble executing DOS commands from within this program.

>If the user types "a:install" everything works fine.  But, if they log to
>the floppy first, then run install ( A:\>install <cr> ) things choke.

>Specifically, the destination directory is not created and so the files
>are all copied into a file in the root directory.  I use the Turbo Pascal
>command exec() to call the following command:

>    \command.com /C md C:\DEST

>I also had trouble logging drives and changing directories under program
>control, but got around that by haveing the install program create the
>appropriate batch file, then executing it...

>Question: am I missing something? Why don't the DOS commands work the
>same as at the command line??

>-- 
>============================================================================
>| Jeff Meyers      |  jmeyers@ecst.csuchico.edu      | 39x43'N  121x48'W   |
>| Chico, Ca 95926  |  KD6DIS@KE6LW.#NOCAL.CA.USA.NA  | Grid: CN80-CM99 ??  |
>============================================================================

Well, ideally I'd like to have more information, but here's a hunch:

Does the floppy disk you're trying to run the utility from have a
copy of COMMAND.COM on it?  If not, and if you're trying to execute
\COMMAND.COM instead of C:\COMMAND.COM, for instance, it probably won't
work -- can't find COMMAND on the floppy disk, so can't execute it.

Also, I don't know which version of Turbo Pascal you're using, but:  does a
command like getenv (or get environment entry) exist in your version?  If so,
you could retrieve the (it _should_ be there) string associated with the
COMSPEC environment variable, and use THAT for the drive-name/directory-path
to a copy of COMMAND.COM to execute.


Just my opinion on what MIGHT be wrong.

One last note:  I once wrote a utility (under Turbo Pascal 3.1 (old, I
know :-)) that does some of the operations (change drive, change
directory, etc.) you describe; problem is, nothing like the  exec  command
was around (had to write my own code to do that).  If I remember correctly,
version 3.1 had a command called  chdir  (change directory) -- does yours?
(Change drive was something else -- I ended up using the DOS-services
(MSDOS ?) function to change disk drive, change file attributes, etc.)
Drop me a line if you'd like a copy of the source code (now just collecting
dust on my disk drive :-).


David Douglas
douglas@usceast.cs.scarolina.edu