Re: checking for a dead MathLink connection
- To: mathgroup at smc.vnet.net
- Subject: [mg23635] Re: checking for a dead MathLink connection
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Thu, 25 May 2000 01:00:45 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <8g5eed$g4b@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi Albert,
I think
"Check[expr, failexpr] evaluates expr, and returns the result, unless \
messages were generated, in which case it evaluates and returns
failexpr. \
Check[expr, failexpr, s1::t1, s2::t2, ... ] checks only for the
specified \
messages."
will help you.
But in gerneral your MathLink connection must be alive until
you terminatet it with Uninstall[] all other cases are an error
of the MathLink child and must corrected in the MathLink
program and *not* by the kernel.
Regards
Jens
Adalbert Hanssen wrote:
>
> Hi, MathGroup,
>
> Links[] tells me, which MathLink connections were opened but not yet
> closed until the command is issued.
>
> Links["file"] tells me, which MathLink connections to "file.exe" (on NT)
> were opened but not yet closed until the command is issued.
>
> Both return a List of LinkObjects (or {}, if there is none).
>
> After Uninstall[link], the link designated by the parameter is closed
> and after this, this connection is no longer reported by Links.
>
> If the other end of a MathLink connection "dies improperly", it is still
> reported by Links.
>
> How can I tell, if a given link is alive? LinkReadyQ is not the right
> one, as it tests, if there are data to be read from the link. There
> must be some function, if you try to use a dead connection, you
> get an error message
>
> LinkObject::linkn: "Argument LinkObject[....]... has an invalid
> LinkObject number; the link may be dead."
>
> I just want the function which does the test resulting in the above
> error message, but before it is put out.
>
> Kind regards
>
> Dipl.-Math. Adalbert Hanszen