How to use fclose() with ActivePerl

[Steve Hay]

Hi,

I have an XS function that gets a FILE * back from a library function that it calls and then tries to PerlIO_importFILE() that into a PerlIO *. Just for completeness my code checks for the (presumably rather unlikely) event that this could fail, and in this case it tidies up by fclose()'ing the now-useless FILE *. Something like this:

FILE *fp;
PerlIO *pfp;

fp = my_library_fn();

if (fp != Null(FILE *)) {
pfp = PerlIO_importFILE(fp, mode);

if (pfp != Nullfp) {
# Good. Do some stuff...
}
else {
# Oh dear. Clean up...
fclose(fp);
# Return failure.
}
}
else {
# Oh dear.
# Return failure.
}

My problem is this: When I build this with a Perl that I built it all works fine, but when I build it with ActivePerl I get the following two warnings from the compiler:

warning C4047: 'function' : 'struct _PerlIO ** ' differs in levels of indirection from 'struct _iobuf *'
warning C4024: 'Perl_PerlIO_close' : different types for formal and actual parameter 2

The line numbers in the error messages refer to several lines before the fclose() in the above code snippet, but if I comment out that fclose() then it all works OK. Why does this happen?

The only difference between my own Perl build and ActivePerl is the build options -- I'm using ActivePerl 5.8.0 Build 804, and my Perl is built from those sources. Specifically, ActivePerl has MULTIPLICITY, USE_ITHREADS, USE_LARGE_FILES, PERL_IMPLICIT_CONTEXT, PERL_IMPLICIT_SYS and uses the system's malloc(), while my Perl disables all of these and uses Perl's malloc().

I suspect the difference arises from the use/non-use of PERL_IMPLICIT_SYS, but I can't pin it down.

Can anybody explain what is going on and how to resolve it?

BTW, my XS file specifies "#define PERLIO_NOT_STDIO 0" before including the Perl headers, as described in "perlapio" manpage.
I'm working on Windows XP SP1 with MS VC/C++ 6 SP5.

Thanks

Steve Hay