use strict;
use warnings;
use feature 'say';
use Alien::GSL;
use Math::GSL;
use Math::GSL::SparseMatrix ':all';

my $m = gsl_spmatrix_alloc( 1, 1 );

my $v;

#$v = 3 + (1 << 32); # no problem with this value
#$v = 2 + (1 << 32); # no problem with this value
#$v = 0 + (1 << 32); # no problem with this value
$v = 1 + (1 << 32); # blows up, but only if
                    # gsl_spmatrix_get($m, $v, 0)
                    # is called. 

die if gsl_spmatrix_set( $m, 1, 0, 1.5 );
say gsl_spmatrix_get($m, 1, 0);
say gsl_spmatrix_nnz( $m );
die if gsl_spmatrix_set( $m, $v, 0, 1.75 );
say gsl_spmatrix_get($m, $v, 0); # comment out to avoid blow up
                                  # when $v is 1 + (1 << 32).
                                  # But still gives wrong result
                                  # (for that value only).
say gsl_spmatrix_nnz( $m );