my $h1;
my $h2;
$h2->{'bar'} = 1;
$h1->{'foo'} = $h2;

##</code><code>##

void
mhash1(key1, h1)
  char* key1
  HV* h1
  CODE:
    I32 klen1 = strlen(key1);
    if ( hv_exists(h1, key1, klen1) ) {
    }

##</code><code>##

void
mhash2(key1, h1, key2)
  char* key1
  char* key2
  HV* h1
  CODE:
    I32 klen1 = strlen(key1);
    I32 klen2 = strlen(key2);
    if ( hv_exists(h1, key1, klen1) ) {
      SV** h2r = hv_fetch(h1, key1, klen1, 0);
      HV* h2 = (HV*)*h2r;
      if ( hv_exists(h2, key2, klen2) ) {
        printf("%s\n", "found it!");
      }
    }

##</code><code>##

#!/usr/bin/perl
use strict;
use warnings;
use MyTest;
my $h1;
my $h2;
$h2->{'bar'} = 1;
$h1->{'foo'} = $h2;
MyTest::mhash2('foo', $h1, 'bar');