CODEWITHSUNDEEP
perl
Hannibal
Hannibal

Reputation: 445

Inline::CPP - How to deal with pointers (int*) as arguments of a C function

I'm trying, using the Inline::CPP module, to pass two pointers as arguments to a C function but I get the error No typemap for type int *. Skipping void swapPointer(int *, int *) and I can't figure out what I have to do to achieve my goal. I would like some help, please.

This is my code:

#!/usr/bin/perl

use Inline CPP;

my $x = 1 ;
my $y = 2 ;

swapPointer(\$x, \$y); 
 
print "X:$x Y:$y" ; # expected: $x => 2 and $y => 1

__END__
__CPP__
   
void swapPointer(int* a, int* b)
{
  int tmp = *a;
  *a = *b;
  *b = tmp;
}

Upvotes: 2

Views: 75

Answers (1)

Håkon Hægland
Håkon Hægland

Reputation: 40778

You could try use SV * instead of int *, see this answer for more information. Her is an example:

Here is an example:

use feature qw(say);
use strict;
use warnings;
use Inline 'CPP';

my $x = 1 ;
my $y = 2 ;

swapPointer(\$x, \$y);

say "X:$x Y:$y" ; # expected: $x => 2 and $y => 1

__END__
__CPP__

void swapPointer(SV* rva, SV* rvb)
{
  if (!SvROK(rva)) croak( "first input argument is not a reference" );
  if (!SvROK(rvb)) croak( "second input argument is not a reference" );
  SV *sva = (SV *)SvRV(rva);
  SV *svb = (SV *)SvRV(rvb);
  if (SvROK(sva)) croak( "first input argument is a reference to a reference" );
  if (SvROK(svb)) croak( "second input argument is a reference to a reference" );
  if ( SvTYPE(sva) >= SVt_PVAV ) croak( "first input param is not a scalar reference" );
  if ( SvTYPE(svb) >= SVt_PVAV ) croak( "second input param is not a scalar reference" );
  SV *temp = newSVsv(sva);
  sv_setsv(sva, svb);
  sv_setsv(svb, temp);
  SvREFCNT_dec(temp);  // Free the temporary SV
}

Output:

X:2 Y:1

Upvotes: 3

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