extern "COBOL" {
  void CBLRTN( double p2 );
}

main() {
  double myval = 5;

  CBLRTN(myval);
  printf("myval=%f\n",myval);

}

IDENTIFICATION DIVISION.
PROGRAM-ID. COBRTN.
ENVIRONMENT DIVISION.
DATA DIVISION.
LINKAGE SECTION.
01 X COMP-2.
PROCEDURE DIVISION USING BY REFERENCE X.
     DISPLAY X
     GOBACK.
END PROGRAM COBRTN.