32-bit signed binary integer with extern "C"

IDENTIFICATION DIVISION.
PROGRAM-ID. COBRTN.
ENVIRONMENT DIVISION.
DATA DIVISION.
WORKING-STORAGE SECTION.
01 X PIC S9(9) BINARY.
01 Y PIC S9(9) BINARY.
PROCEDURE DIVISION.
     MOVE 1 TO X.
* X BY VALUE ***
     CALL "CENTRY" USING BY VALUE X
       RETURNING Y.
     GOBACK.
END PROGRAM COBRTN.

#include <stdio.h>
extern "C" {int CENTRY (int x);}

int CENTRY(int x)
{
  int y=2;
  printf("%d %d \n",x,y);
  return y;
}