I've successfully made a shared library that can calculate directory sizes on Win32, and I can link to it via a 100% C utility. Now I want to build a perl module to access the lib. Unfortunately, I'm having some difficulties.

The function in the library is "_dir_size()" and the function I want to expose to perl is "dir_size()". The perl function will work like this:

my $hashref;
my $result = dir_size("C:\\temp", $hashref);
print "File count = ", $hashref->{FileCount}, "\n";
print "Dir size = ", $hashref->{LowSize}, "\n";

[download]

I have this XS function defined:

int 
dir_size (dirname,dirinfo,permsdie=0,otherdie=0)
    PREINIT:
        AV *errs            = newAV();
        HV *newdirinfo            = newHV();
        unsigned long hightotalsize    = 0;
        unsigned long lowtotalsize    = 0;
        long filecount            = 0;
        long dircount            = 0;
    INPUT:
        SV *dirinfo;
        char *dirname;
        int permsdie;
        int otherdie;
    CODE:
        RETVAL = _dir_size (errs, permsdie, otherdie, dirname, &highto
+talsize, &lowtotalsize, &filecount, &dircount);
        hv_store(newdirinfo, "Errors",        6, newRV((SV *)errs), 0)
+;
        hv_store(newdirinfo, "HighSize",    8, newSVuv(hightotalsize),
+ 0);
        hv_store(newdirinfo, "LowSize",        7, newSVuv(lowtotalsize
+), 0);
        hv_store(newdirinfo, "FileCount",    9, newSViv(filecount), 0)
+;
        hv_store(newdirinfo, "DirCount",    8, newSViv(dircount), 0);
        dirinfo = newRV_noinc((SV *)newdirinfo);
        printf("Found %i files\n", filecount);
    OUTPUT:
        dirinfo
        RETVAL

[download]

The printf() call in the above XS spits out the right number, but back in perl, my $hashref is undef. Any ideas?

In reply to XS returning undef? by meetraz

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