Path: utzoo!attcan!uunet!snorkelwacker!ai-lab!friedman@apple-gunkies.ai.mit.edu
From: friedman@apple-gunkies.ai.mit.edu (Noah Friedman)
Newsgroups: comp.os.msdos.programmer
Subject: Re: Child processes in Mess-Dos
Summary: Use execvp()
Message-ID: <11134@life.ai.mit.edu>
Date: 2 Oct 90 17:17:20 GMT
References: <4469@bwdls58.UUCP>
Sender: news@ai.mit.edu
Organization: The Free Software Foundation
Lines: 25

In article <4469@bwdls58.UUCP> mlord@bwdls58.bnr.ca (Mark Lord) writes:
>Ok.. I believe the difference here is whether or not the complete path is
>given for the command.  If fully qualified, COMMAND.COM is not needed,
>otherwise it probably is needed to do the PATH search and actual invocation.
>
>Ie.  "C:\BIN\MAPMEM.COM"  -- probably does not need COMMAND.COM
>     "MAPMEM"             -- probably DOES need COMMAND.COM
>
>I say probably because my Machine is unavailable to verify this theory for now.

Most C libraries have an execvp() function which will search directories in
the PATH environment variable if the program name is not a fully-qualified
pathname. If you are unsure, you can always use this function or attempt to
resolve the full pathname in your program.

I suspect, however, that the EXEC call does *not* use COMMAND.COM, but
rather, uses the current path when a filename is not fully qualified. This
would be consistent with the behavior of other DOS system calls.

I cannot at the moment verify this either since my XT is down, but I seem
to remember from experience that this is correct.

---
Noah Friedman
friedman@ai.mit.edu