[fpc-pascal]No wait execution and redirection of stdin and stdout

[XHajT03 at mbox.vol.cz]

From:           	"Peter H.M. Brooks" <peter at new.co.za>
To:             	<fpc-pascal at deadlock.et.tudelft.nl>
Date sent:      	Tue, 27 Aug 2002 20:24:32 +0200
Organization:   	Psyche Trading Company
Subject:        	[fpc-pascal]No wait execution and redirection of stdin and stdout
Send reply to:  	fpc-pascal at deadlock.et.tudelft.nl

> Sadly I need to do development under msdros.
.
.
> - Firstly I'd like to launch a program with no wait and then check for
> its completion later.

 If you're talking about real MS-DOS (i.e. no Winslows on top of it, 
etc.), you just can't do that - there's no multitasking support in MS-
DOS itself, so you'd first have to implement this one yourself (or 
find some solution created by somebody else). There are some 
multitaskers (e.g. Desqview) - if you're talking about something like 
this, you should specify it, since every such product has its own 
API. I could probably tell you something more if I know what you're 
trying to do (you might be able to run two tasks in parallel by 
hooking some interrupts for example).  

> - Secondly, when launching a program I'd like to redirect its stdin
> and stdout equivalents so that I can write to it and read from it
> while it is executing - clearly I need to be able to do the above
> first!

 Plain executing with redirecting input / output / error and _with_ 
waiting is of course possible, you'd just have to process the results 
after the child process is finished.

> - I'd also like to be able to send signals to programs that I have
> launched to terminate them or establish their current state.

 See above - there's no multitasking in DOS by default, so there's 
generally just one process which has full control of everything (i.e. 
once you launch a child process it runs until it terminates itself).

Tomas