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Re: MathLink

  • To: mathgroup at
  • Subject: [mg25994] Re: [mg25966] MathLink
  • From: John Fultz <jfultz at>
  • Date: Wed, 15 Nov 2000 02:09:44 -0500 (EST)
  • Sender: owner-wri-mathgroup at

You don't have the proper quoting here.  The command-line parser won't
be able to tell that the spaces in the pathname aren't actually argument
delimiters.  Throw a \" before and after the pathname to the kernel.
Otherwise, it tries to execute "C:\\Program", and then gets confused when
it doesn't find C:\Program.exe.  Having not found the program, it will,
of course, ask you where it is.

For example,

"-linkname \"C:\\Program Files\\Wolfram Research\\Mathematica\\4.0\\MathKernel\" -linkmode launch"

A further problem comes in that MathKernel really should be launched
with the '-mathlink' argument.  But that would *also* need to be quoted,
and now things start to get messy.  Well, there are two solutions.
The easy solution is to use a version of the filename which doesn't have
spaces...for example, we could exploit the short filenames on Windows
to do...

"-linkname \"C:\\Progra~1\\Wolfra~1\\Mathematica\\4.0\\MathKernel -mathlink\" -linkmode launch"

The better solution is to use another form of MLOpen which allows you to
pass in string arrays such as MLOpenArgV.  Here's some sample code which
I didn't actually try compiling, but ought to point you in the right

// Warning...I didn't actually compile this, so there may be typos, but it
// should give you the idea.

const char * mlargs[4] = {"-linkname",
	"C:\\Program Files\\Wolfram Research\\Mathematica\\4.0\\MathKernel -mathlink",
long err;
MLINK link;
MLEnvironment env = MLInitialize(NULL);

link = MLOpenArgV(env, mlargs, mlargs+4, &err);

// or you could do the slightly more sensible, but undocumented
// call below...

link = MLOpenInEnv(env, mlargs, 4, &err);


John Fultz
jfultz at
User Interface Group
Wolfram Research, Inc.

> I am trying to call a mathematica function from my C program (Win98). I use
> the enclosed function to
> start the kernel. The program works fine but I cannot get rid of the file
> select windows which pops up
> and ask me to select a mathlink program. I would be grateful for any
> suggestions as to how to fix this
> problem.
> Thanks,
> Mirek Latka
> void init_and_openlink()
> {
>  long err;
>  ep =  MLInitialize( (MLParametersPointer)0);
>  if( ep == (MLENV)0) exit(1);
>  atexit( deinit);
>  lp=MLOpenString(ep,"-linkname C:\\Program Files\\Wolfram
> Research\\Mathematica\\4.0\\MathKernel.exe -linkmode launch",&err);
>  if(lp == (MLINK)0) exit(2);
>  atexit( closelink);
> }

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