Structure with extern "COBOL"

IDENTIFICATION DIVISION.
PROGRAM-ID. COBRTN.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 STRUC1.
     05 S11 PIC S9(9) BINARY VALUE 1.
     05 S12 PIC S9(9) BINARY VALUE 2.
01 STRUC2.
     05 S21 PIC S9(9) BINARY VALUE 3.
     05 S22 PIC S9(9) BINARY VALUE 4.
PROCEDURE DIVISION.
* STRUC1 BY VALUE STRUC2 BY REFERENCE ***
     CALL "CENTRY"
       USING BY CONTENT STRUC1
             BY REFERENCE STRUC2.
     GOBACK.
END PROGRAM COBRTN.

#include <stdio.h>
struct stype {
  int S1;
  int S2;  };
extern "COBOL" {void CENTRY
     (struct stype struc1,
      struct stype *struc2);}

void CENTRY(struct stype struc1,
      struct stype *struc2)
{
printf("%d %d %d %d \n",struc1.s1,
      struc1.s2,struc2->s1,struc2->s2);
return;
}