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From: evans@decvax.DEC.COM (Marc Evans)
Newsgroups: comp.os.vms,comp.windows.x
Subject: Re: XtAddInput and VMS DEC Windows
Message-ID: <451@decvax.decvax.dec.com.UUCP>
Date: 21 Nov 90 12:04:27 GMT
References: <1990Nov20.184509.3252@objy.com>
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Reply-To: evans@decvax.DEC.COM
Followup-To: comp.os.vms
Organization: Synergytics
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In article <1990Nov20.184509.3252@objy.com>, ricks@prefect.objy.com (Rick L. Spickelmier) writes:
|> I'm trying to get XtAddInput to work on VMS with the input 
|> coming from a pipe connected to a subprocess (created with
|> vfork/execv).  I can create pipes, dup them to 0 and 1,
|> vfork/execv the child and communicate just fine (child
|> uses stdin and stdout, parent uses the pipes).  However,
|> if I try to use XtAddInput (rather than explicit reads
|> in the parent) I just hang...  Does anybody use XtAddInput
|> under VMS?  Is it with a subprocess via pipes?  If so,
|> could you send a code fragment?

Your problem likely comes from the fact that the VMS folk decided to implement
XtAddInput (and friends) in an OS dependent manner. Instead of the file descriptor
and mask arguments that we all use and love on our POSIX systems, VMS choose to
use AST and STATUS in their place. What does this mean? Well, it means that your
program which builds easily under most unix's will need to be hacked for VMS,
sometimes quite extensively 8-(. What should be real interresting is when VMS
actually becomes POSIX compliant, because the implementation of XtAddInput (and
friends) will be required to use the file descriptor and mask style of
implementation, which will break binary and compile time backward compatability...

- Marc

-- 
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Marc Evans - WB1GRH - evans@decvax.DEC.COM  | Synergytics     (603)635-8876
      Unix and X Software Contractor        | 21 Hinds Ln, Pelham, NH 03076
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