Path: utzoo!attcan!ncrcan!ziebmef!mikek
From: mikek@ziebmef.uucp (Mike King)
Newsgroups: comp.windows.ms
Subject: Spawning in Windows
Keywords: spawn exec
Message-ID: <1989May19.112713.17785@ziebmef.uucp>
Date: 19 May 89 15:27:12 GMT
Organization: Ziebmef Public Access Unix, Toronto, Canada
Lines: 24

Recently I posted an article asking for help spawning other apps from 
within a Windows app.  I received a number of mail responses and I tried
out all of the suggestions.  Since I've seen others asking the same question
as I did I thought I would present my findings.

1 - spawn? from the standard library will work --- most of the time!
    Sometimes it seems to crash in a nasty way.

2 - using DOS function 4B works --- most of the time!
    Sometimes it will crash as well, usually with ENOMEM.

3 - the winning suggestion was received from Microsoft, and confirmed by
    someone from hDC (sorry I forget your name).

Here goes:
     
        /* reliable Windows spawn code */
        GlobalCompact((DWORD)-1);    /* compact the global heap */
        LockData(0);                 /* lock down your data segment */
        spawnl(P_NOWAIT, "newapp.exe", "newapp", NULL);
        UnlockData(0);               /* unlock your data segment */

    The interesting bits are the GlobalCompact - to give yourself some room,
    and the LockData - stop data pointers from becoming orphans.