In answer to your helpful questions, if I do not specify any directory in my script then I then get the same error message as I did when I specified .Inline/. The error message says that it cannot autogenerate a config file in .Inline/. (.Inline/ is the default according to my reading of perldoc)

If I remove the .Inline directory and I do not specify a directory then the error message says "Couldn't find an appropriate directory for Inline to use". Which is interesting, because I thought it would create such a directory for me, but it does not.

Thanks for your help. Getting recalcitrant modules to run is a lot of work.

Well, it works for me under 5.6.1 if I create the .Inline directory first. This may be a 5.005 problem. Can you run the following (with appropriate paths):

use strict;
use Inline (Config => DIRECTORY => '/home/ned/.Inline',);
use Inline 'C';
greet('Ingy');
greet(42);
__END__
__C__
void greet(char* name) {
 printf("Hello %s!\n", name);
}
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On my system, it writes a config file in /home/ned/.Inline/config that looks like:

version : 0.42
languages : %
    C : C
    Foo : Foo
    c : C
    foo : Foo
types : %
    C : compiled
    Foo : interpreted
modules : %
    C : Inline::C
    Foo : Inline::Foo
suffixes : %
    C : so
    Foo : foo
[download]

Thank you very much BikeNomad. I ran your script, and I got the same error message as before, saying that the autogeneration of the config failed.

It is reasonably apparent that I am dealing with either a 5.005 problem or a circa 1997 NCR MP-RAS Unix problem.

I am not even certain that XS or Swig would work, assuming that I had the time and skills to coerce them to do so.

Therefore: PLAN B. Instead of calling C from Perl, I will have Perl write its input to a special file. A C program called with backticks will read the input and print the output.

Not the most elegant way to do things, but the best option now that the Inline.pm/MP-RAS/5.005 combination has proven to be a big problem.