The following example includes the ALGOL host program and an ALGOL subprogram that references connection block items from outside the connection block.

ALGOL Host Program

BEGIN
TYPE CONNECTION BLOCK CB;
  BEGIN
  REAL PROCEDURE R1;
     BEGIN
     REAL R;
     R:= 5.5
     R1:= R;
     END R1;
  END CB;

CB SINGLE LIBRARY CL;

PROCEDURE EXTERNAL_PROC;
   EXTERNAL;

EXTERNAL_PROC;
END.

ALGOL Subprogram

[
 TYPE CONNECTION BLOCK CB; FORWARD;
 CB SINGLE LIBRARY CL;
]TYPE CONNECTION BLOCK CB;  % CB is fully specified here
   BEGIN
   REAL PROCEDURE R1;
      BEGIN
      REAL R;
      R:=5.5;
      R1:=R;
      END R1;
   END CB;

$ SET LEVEL 3
PROCEDURE EXTERNAL_PROC;
   BEGIN
   REAL REEL;
   REEL := CL.R1;
   END.

The following example includes an ALGOL host program that declares a connection block with imported library objects and an external procedure. Also included is an example of a subprogram containing the procedure to be bound and, for completeness, an example of the library file.

ALGOL Library Program

BEGIN
EVENT EV;
TYPE CONNECTION BLOCK CB;
     BEGIN
     EBCDIC ARRAY OUTPUTMSG[0:30];
     PROCEDURE SENDOUTPUT;
       BEGIN
       DISPLAY (STRING (OUTPUTMSG[0],10));
       END;

     EXPORT
       OUTPUTMSG (READWRITE),
       SENDOUTPUT;
       END CB;

CB SINGLE LIBRARY CL_LIB;

EXPORT EV;

READYCL (CL_LIB);

FREEZE (TEMPORARY);
END.

ALGOL Host Program

BEGIN
TYPE CONNECTION BLOCK CB;
     BEGIN
     REAL R;
     IMPORTED EBCDIC ARRAY        % Imported library object
        OUTPUTMSG[0] (READWRITE);
     PROCEDURE SENDOUTPUT;        % Imported library object
        IMPORTED;
     PROCEDURE P1;
        EXTERNAL;
     END CB;

CB SINGLE LIBRARY CL
    (AUTOLINK=TRUE,
     INTERFACENAME="CL_LIB.",
     TITLE="OBJECT/IMPORTED/CL/LIB."
     );

CL.P1;
END.

ALGOL Subprogram

$ set level 4
[TYPE CONNECTION BLOCK CB; EXTERNAL; ]

 TYPE CONNECTION BLOCK CB;
      BEGIN
      IMPORTED EBCDIC ARRAY        % Imported library object
         OUTPUTMSG[0] (READWRITE);
      PROCEDURE SENDOUTPUT;              % Imported library object
         IMPORTED;
      PROCEDURE P1;
         PENDING;
      END CB;

PROCEDURE CB.P1;
  BEGIN
  REPLACE OUTPUTMSG[0] BY "IN P1";
  SENDOUTPUT;
  END P1.