Can’t Reference EXTERNAL File After CALL to ENTRY Point; Hangs
PSS ID Number: Q50465 Article last modified on 04-20-1993
3.00 3.00a | 3.00 3.00a MS-DOS | OS/2
| The information in this article applies to: |
| - Microsoft COBOL for MS-DOS and OS/2, versions 3.0 and 3.0a |
Summary: An attempt to reference an EXTERNAL FILE from within a program CALLed using an ENTRY POINT will cause one of the following symptoms: 1. A machine hang 2. A “protection violation” under MS OS/2 3. Run-time error 166 “Recursive COBOL call illegal” and/or run-time error 161 “Illegal intermediate code” 4. Display of run-time error 203 “Call parameter not supplied” when run in the ANIMATOR, even though there are no parameters missing A program CALLed at an ENTRY point can reference files that are not EXTERNAL. Microsoft has confirmed this to be a problem with Microsoft COBOL Compiler versions 3.0 and 3.0a for MS-DOS and MS OS/2. This problem has been corrected in Microsoft COBOL Professional Development System version 4.0 for MS-DOS and MS OS/2.
More Information: This error occurs whether the FILE-ID is hard coded into the program or assigned to a WORKING STORAGE DATA-NAME. This error is not dependent on how EXTFH and EXTERNL are linked to the code, and it happens regardless of the DIRECTIVES set. FILES referenced from a CALLed program work correctly. To work around the problem, do not use an ENTRY point. Instead, make a CALL to the second program using its PROGRAM-ID or its disk name. Then, pass a parameter stating where to begin the program. The parameter could be used to state where to GO TO in the second program. For a more structured approach, the parameter could be used to indicate which PARAGRAPH should be performed.
Code Example
The following program demonstrates the problem: Program 1: $SET NOLITLINK ERRQ *************************** * PROG1.COB ************************** ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT EXT-FILE ASSIGN TO DISK ORGANIZATION IS LINE SEQUENTIAL ACCESS MODE IS SEQUENTIAL. DATA DIVISION. FILE SECTION. FD EXT-FILE IS EXTERNAL VALUE OF FILE-ID IS FILE-NAME. 01 EXT-FILE-REC PIC X(80). WORKING-STORAGE SECTION. 77 FILE-NAME PIC X(12) VALUE “TESTFILE.DAT”. PROCEDURE DIVISION. START-TEST. OPEN OUTPUT EXT-FILE. * make initial call so the entry point will be valid CALL “PROG2”. CALL “entry-pt”. CANCEL “PROG2”. CLOSE EXT-FILE. * NOW THE FILE CONTAINS “HELLO”. READ IT AND PRINT IT OUT. OPEN INPUT EXT-FILE. READ EXT-FILE. DISPLAY EXT-FILE-REC. CLOSE EXT-FILE. STOP RUN. Program 2: $SET NOLITLINK ERRQ *************************** * PROG2.COB ************************** ENVIRONMENT DIVISION. INPUT-OUTPUT SECTION. FILE-CONTROL. SELECT EXT-FILE ASSIGN TO DISK ORGANIZATION IS LINE SEQUENTIAL ACCESS MODE IS SEQUENTIAL. DATA DIVISION. FILE SECTION. FD EXT-FILE EXTERNAL VALUE OF FILE-ID IS “TESTFILE.DAT”. 01 EXT-FILE-REC PIC X(80). WORKING-STORAGE SECTION. 77 FILE-NAME PIC X(12) VALUE “TESTFILE.DAT”. PROCEDURE DIVISION. DISPLAY “IN PROG2”. GOBACK. ENTRY “entry-pt”. START-TEST. MOVE “HELLO” TO EXT-FILE-REC. WRITE EXT-FILE-REC. GOBACK. EXIT PROGRAM.
Additional reference words: 3.00 3.00a Copyright Microsoft Corporation 1993.
