#include <stdio.h>
#include <stdlib.h>

/* Does NOT cause memory error */
typedef struct __attribute__((__packed__))
{
   unsigned short chr;
   unsigned int loc;
} GENOME_LOC_TYPE_2;

/* Causes memory error */
typedef struct __attribute__((__packed__))
{
   unsigned chr            :16;
   unsigned loc            :32;
} GENOME_LOC_TYPE;

void
print_mapped_location( GENOME_LOC_TYPE loc )
{
   printf( "%i\n", loc.loc );
}

int main( int argc, char* argv )
{
   char* data;
   data = malloc(12*sizeof(char));

   GENOME_LOC_TYPE* gen_array
       = (GENOME_LOC_TYPE*) data;
   gen_array[0].loc = 0;
   gen_array[1].loc = 1;

   /* Make sure the structure is actually 6 bytes */
   printf("Gen Loc Type Size: %zu\n", sizeof(GENOME_LOC_TYPE) );

   /* Works fine. */
   printf( "%i\n", gen_array[1].loc );

   /* Works fine */
   GENOME_LOC_TYPE loc = gen_array[1];
   print_mapped_location( loc );

   /* Causes valgrind error */
   /* Cause -lefence segfault */
   print_mapped_location( gen_array[1] );

   free( data );
}