Inline CPP function not found

markov has asked for the wisdom of the Perl Monks concerning the following question:

Dear Monks, I try to get this to work:

use Inline CPP => Config => ENABLE => 'STD_IOSTREAM';
use Inline CPP;

print "g = ", g(12), "\n";

my ($a, $b, $c) = (1, 2, 3);
my ($x, $y, $z);
my $error = f($a, $b, $c, $x, $y, $z);
print " --> $x, $y, $z (e=$error)\n";

__END__
__CPP__

#include <iostream>
using namespace std;

int f(double a, double b, double c, double& x, double& y, double& z) {
    int error = -2;
    x = a +42;
    y = b +42;
    z = c +42;
    return error;
}

int g(int b) {
   return 42;
}
[download]

But the output is

g = 42
Use of inherited AUTOLOAD for non-method main::f() is deprecated at ./
+z line 12.
Can't locate auto/main/f.al in @INC (@INC contains: ...)
[download]

How do I get this to work? Thanks in advance.

Comment on Inline CPP function not found Select or Download Code

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Re: Inline CPP function not found by ikegami (Patriarch) on May 16, 2011 at 21:00 UTC
Does it run if you switch `double&` to `double`? If so, it's a lack of entry in the typemap to handle `double&`. Update: I managed to get Inline::CPP installed (with a patch from a bug report), and confirmed that the problem is indeed that `double&` isn't handled. I was able to make the code work using the following: `int f(double a, double b, double c, SV* x, SV* y, SV* z) { int error = -2; SvUPGRADE(x,SVt_NV); SvNV_set(x,a+42); SvNOK_on(x); SvSETMAGIC(x); SvUPGRADE(y,SVt_NV); SvNV_set(y,b+42); SvNOK_on(y); SvSETMAGIC(y); SvUPGRADE(z,SVt_NV); SvNV_set(z,c+42); SvNOK_on(z); SvSETMAGIC(z); return error; }` [download] It may also be possible to keep the original prototype by creating a typemap entry for `double&`.	[reply] [d/l] [select]
Re^2: Inline CPP function not found by markov (Scribe) on May 16, 2011 at 21:29 UTC
Very useful, thank you. With a wrapper I can call the original function with it.	[reply]
Re: Inline CPP function not found by educated_foo (Vicar) on May 16, 2011 at 21:01 UTC
As far as I can tell from Inline::CPP::grammar, Inline::CPP doesn't handle reference parameters, so it's probably skipping your function. Try using pointers instead. EDIT: I'm wrong -- it does at least parse it, so while I'm pretty sure Inline::CPP is skipping it as something it can't handle, I'm not sure what the problem is.	[reply]
Re^2: Inline CPP function not found by markov (Scribe) on May 16, 2011 at 21:15 UTC
It think the parser does understand it. In Inline/CPP/grammar.pm `type1: TYPE star(s?) star: '' \| '&'` [download] So, if 'double ' is parsed, than 'double &' as well. Probably I do need to do something with typemaps or function rewrites. Would be nice if someone knows what.	[reply] [d/l]