Path: utzoo!utgpu!attcan!uunet!lll-winken!lll-tis!ames!mailrus!uwmcsd1!nic.MR.NET!umn-cs!mmm!ems!questar!brent
From: brent@questar.QUESTAR.MN.ORG (Brent Nordquist)
Newsgroups: comp.sys.amiga.tech
Subject: Lattice 4.0 forkl() problem
Message-ID: <1222@questar.QUESTAR.MN.ORG>
Date: 26 Jul 88 21:01:59 GMT
Reply-To: brent@questar.QUESTAR.MN.ORG (Brent Nordquist)
Followup-To: comp.sys.amiga.tech
Organization: Questar Data Systems, Minneapolis, MN
Lines: 36
References:

[ Elf: "crunch crunch crunch... mmmmm... thank you!" ]
[ Thanks to the author of DiskSounds for a good laugh at 3 A.M... ]

I am trying to get the Lattice 4.0 forkl() function to work "as
advertised" in the manual, to no avail.

I need to be able to start up another program with its stdin redirected
from somewhere else.  For example, the first process opens a file, sets
the stdin of the second process to be that file descriptor, and then
forks; then the second process, when reading from stdin, would be
reading from the file.

(BTW, I *don't* want to use Execute() or system() or ____(), because
I don't want to have to run off to SYS: to get the 'Run' command each
time.  [Tacky!]  I also need them to run concurrently.)

When I call forkl() with (struct ForkEnv *)NULL it works fine, with
the new process inheriting stdin from the current process.  Now, the
manual says I should also be able to pass a (struct ForkEnv *) whose
*fields* are NULL, and any NULL field will receive a default value.
So, I tried it, and I get the Guru.

First of all, the printed structure definition is wrong; the fields are
'std_in' and 'std_out,' not 'stdin' and 'stdout.'  (Wish I had the
manual with me so I could quote the page number.)  Also, the .h file
says they're BPTR's and not long's.  Are these 'file handles' returned
by open(), or is this something Amiga-specific?  (Can you say, "naive-
Amiga-programmer-used-to-mainframe-C?"  :-)

Perhaps forkl() isn't the best way to start up another process; can
someone give me some help?  Short example code would be invaluable!

Thanks!
-- 
Brent Nordquist                          Bachelorhood remaining:
brent@questar.mn.org                     
amdahl!bungia!questar!brent              20 weeks, 3 days, 19:00