#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <string.h>

#define  SOCKPATH	"localsocket"

void err_sys( const char * const );



int main()
{
  struct sockaddr_un   uaddr, caddr;
  int                  usock, res;
  char                 buffer[32] = "";
  socklen_t            len;

  memset( &uaddr, 0, sizeof(uaddr) );
  uaddr.sun_family = AF_LOCAL;
  strcpy( uaddr.sun_path, SOCKPATH );

  if( ( usock = socket( PF_LOCAL, SOCK_DGRAM, 0 ) ) == -1 )
    err_sys( "socket()" );
  printf( "User Datagram Socket %d\n", usock );

  printf( "uaddr sockaddr_un has %d bytes\n", (len=SUN_LEN(&uaddr)) );
  if( sendto( usock, "Hail", 4, 0, (struct sockaddr*)&uaddr, len ) == -1 )
    err_sys( "sendto()" );

  printf( "caddr sockaddr_un has %d bytes\n", (len=SUN_LEN(&caddr)) );
  if( recvfrom( usock, buffer, sizeof(buffer), 0,
    (struct sockaddr*)&caddr, &len ) == -1 )
    err_sys( "recvfrom()" );

  printf( "Received %d bytes\n", res );
  printf( "Buffer now is \"%s\"\n", buffer );
}



void err_sys( const char * const mesg )
{
  perror( mesg );
  exit( -1 );
}