Following the perlxstut, in example 5 I get the following error:

   Mytest.c:251:2: error: too few arguments to function 'statfs'
[download]

The example creates a module function statfs that is tested like this in t/Mytest.t:

my @a;
@a = &Mytest::my_statfs("/blech"); # Test non-existent file/directory
ok( scalar(@a) == 1 && $a[0] == 2 );
@a = &Mytest::my_statfs("/");      # Test existing file/directory
is ( scalar(@a), 7 );
[download]

In other words, the function returns a list.

In Mytest.xs:

#include <sys/vfs.h>
    ...
void
statfs(path)
        char * path
    INIT:
        int i;
        struct statfs buf;

    PCODE:
        i = statfs(path, &buf);
        if (i == 0) {
                XPUSHs(sv_2mortal(newSVnv(buf.f_bavail)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_bfree)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_blocks)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_bsize)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_ffree)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_files)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_type)));
        } else {
                XPUSHs(sv_2mortal(newSVnv(errno)));
        }
[download]

The Makefile.PL generates the following C code:

XS_EUPXS(XS_Mytest_statfs)
{
    dVAR; dXSARGS;
    if (items != 1)
       croak_xs_usage(cv,  "path");
    {
        char *  path = (char *)SvPV_nolen(ST(0))
;
#line 43 "Mytest.xs"
        int i;
        struct statfs buf;

    PCODE:
        i = statfs(path, &buf);
        if (i == 0) {
                XPUSHs(sv_2mortal(newSVnv(buf.f_bavail)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_bfree)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_blocks)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_bsize)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_ffree)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_files)));
                XPUSHs(sv_2mortal(newSVnv(buf.f_type)));
        } else {
                XPUSHs(sv_2mortal(newSVnv(errno)));
        }
#line 250 "Mytest.c"

        statfs(path);
    }
    XSRETURN_EMPTY;
}
[download]

Look near the end of this function. Why is this call to statfs being generated? I have tried to call the module function "my_statfs" instead of "statfs", Then the call near the end of the function becomes my_statfs(buf), while the call to the actual library function statfs remains statfs(path, buf), and the compiler message becomes "undefined reference to `my_statfs'".

Why is this call being generated? What am I doing wrong?

And, is XSRETURN_EMPTY the appropriate macro for a function that returns a non-empty list?

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.