[net.micro.amiga] Fork Impossible, Exec Probable

dillon@CORY.BERKELEY.EDU (Matt Dillon) (10/09/86)

	Not that I'm about to tackle exec myself ... only someone with
full BCPL startup specs would be able to do that.  However, I see no reason
why you couldn't deallocate your segment first, then allocate the new 
program's segment (after checking to be sure it's a proper executable), 
simply AllocMem some memory and place the execstrap in it.. then have it
unload the first program, load and execute the second, and then free itself/
kill itself (I believe you can specify certain memory to be Free'd 
automatically on exit)

	Without Fork I don't see what use a UNIX exec will be, though.

					-Matt

lwall@sdcrdcf.UUCP (Larry Wall) (10/10/86)

(Purists stop reading here.)

Fork may be impossible, but how about vfork?  You wouldn't have to do 
any relocation, just establish a separate thread of execution.  And some
way to tell from exec which thread you were running, so you know whether
to start up a new process or not.

Yeah, I know it's gross, but it would handle 90% or so of forks people do.

Larry Wall
{allegra,burdvax,cbosgd,hplabs,ihnp4,sdcsvax}!sdcrdcf!lwall