Re: Inline CPP Question/Issue

----- Original Message ----- 
From: "David Oswald" <[email protected]>
To: "McIntyre, Shane K." <[email protected]>; "inline" <[email protected]>
Sent: Friday, July 13, 2012 4:16 AM
Subject: Re: Inline CPP Question/Issue


> On Thu, Jul 12, 2012 at 11:03 AM, McIntyre, Shane K.
> <[email protected]> wrote:
>> I am writing a Perl module (.pm file) that has C++ code in it. When I
>> attempt to start up apache and the Perl modules get compiled the C++ 
>> method
>> in the file does not get bound to Perl.

That generally means that everything has compiled ok - it's just that 
there's a problem in the perl bindings.

>>  I am not having the same issue with
>> other Perl Modules where I use Inline C only ones where I have Inline 
>> CPP.
>> I am using Perl version 5.8.8.  Is there something different that needs 
>> to
>> be done for C++ vs. C?

Not really, but are you using current versions of Inline::C and Inline::CPP 
?

>> Right now I have a very basic Perl Module that I’m
>> just trying to get to work.  The code is below.  Any help/guidance you 
>> could
>> give me would be appreciated.
>>
>>
>>
>> use strict;
>>
>>
>>
>> use Inline CPP => (‘Config’ =>
>>
>>                                      DIRECTORY =>
>> ‘/projects/langid/apache/_Inline’,
>>
>>                                    );
>>
>>
>>
>> use Inline CPP => <<’END_CPP’;
>>
>>
>>
>> double factorial (int x) {
>>
>>     int i;
>>
>>     double result = 1;
>>
>>     for (i=2; i<=x; i++) result *=I;
>>
>>     return result;
>>
>> }
>>
>> END_CPP
>>
>> 1;

There's a typo in the code - '*=I' should be '*=i'.
But that shouldn't cause the error you're getting.

I *think* 5.8.8 should know how to return a double but just in case it 
doesn't, try this version of the function:

SV * factorial (int x) {
    int i;
    double result = 1;
    for (i=2; i<=x; i++) result *=i;
    return newSVnv(result);
}

If that works, but reverting to 'double' fails, then it's just that your 
perl typemap doesn't provide the necessary information on how to return a 
double.
In that case, the typemap could be fixed - but it's probably easier (and 
certainly no less efficient) to use the function as I have written it. Or 
update to a later version of perl.

Cheers,
Rob