Interfacing with C (Windows 98)

I have been trying (unsuccessfully) to execute a C function from Eclipse. I
compiled file (exporting the function), linked eclipse.lib as required and
ended up with a dll file. The file is loaded ok from eclipse. But when I
try to map the function into a predicate using

external(func/1, p_func)

I get the following error:

External function does not exist in external_(func / 1, p_func, eclipse)

*** compilation aborted
before line 2 in the file //E/driver.pl
calling an undefined procedure end_of_file in module eclipse


I am using Visual C++ 5.0 and Eclipse 5.0. The exact definition of the
function I am trying to use is:

int p_func(value val, type tag)
{
	Check_Integer(tag);
	Succeed;
}

I would appreciate any help.

Many thanks,

Loizos Michael