Syntax and Behavior
• The PROGRAM-ID paragraph must be explicitly declared, and the name of the program must match the name of the source file.
• If a paragraph is declared, then its parent section must be declared as well. For example, INPUT-OUTPUT SECTION must be declared above FILE-CONTROL.
• Only numeric data items can be used to receive the special register CRT STATUS.
• USAGE POINTER data items are translated into numeric items and cannot be passed to external C language functions, unless the “-cp” compiler option is used. If “-cp” is used, pointers are natively handled and can be passed to external C language functions.
• The LOCK THREAD and UNLOCK THREAD statements are not supported. Synchronization can be achieved using the
SYNCHRONIZED statement.
• The CANCEL SORT instruction is not supported.
• A Picture description cannot be distributed on multiple lines. The following code would not compile:
01 COM-02 PIC XBXBXBXBXBXBXBXBXBXBXBXBXBXBX - BXBXBXBXBXBXBXBXBXBXBXBXBXBXBXBX. |
• OCCURS indexes are checked only at runtime, not at compile-time.
• If the JUSTIFIED clause is declared for a control, it must appear immediately after the PICTURE clause.
• It's not possible to ACCEPT or DISPLAY a control that has subordinate controls directly below it. Consider the following screen, for example:
01 SCREEN. 03 FR FRAME. 05 EF ENTRY-FIELD. |
You can ACCEPT and DISPLAY EF, but you can’t ACCEPT or DISPLAY FR. In order to ACCEPT or DISPLAY FR, you should define it at the same level of EF.
• The "RECEIVE MyMessage FROM ANY THREAD" statement must include the NO WAIT statement, or its equivalent, BEFORE TIME 0. Any other timeout is not supported. For example, the following code below will not compile:
RECEIVE MyMessage FROM ANY THREAD RECEIVE MyMessage FROM ANY THREAD BEFORE TIME 1 |
It must be changed to:
RECEIVE MyMessage FROM ANY THREAD NO WAIT RECEIVE MyMessage FROM ANY THREAD BEFORE TIME 0 |
• ActiveX support is not provided. Third-party tools must be used. Contact your Veryant representative for more information.
• Data items defined as USAGE UNSIGNED-LONG or USAGE SIGNED-LONG are 8 bytes long. To declare a 4-byte native data item, it must be PIC 9(9) COMP-5 or PIC S9(9) COMP-5.
• If used, the ENTRY Statement must be declared at the beginning of the paragraph.
• Items defined in the LINKAGE section must be referenced also in the USING phrase. In ACUCOBOL-GT it is not mandatory. You can rely on the
-wlu compiler option to find out this kind of issue in the source files.
• Subordinate items of a group item in the LINKAGE section cannot be referenced in the USING phrase. The entire group must be referenced. The following syntax is not supported by isCOBOL:
LINKAGE SECTION. 01 GROUP-ITEM. 03 ITEM-1 PIC XX. 03 ITEM-2 PIC X(10). PROCEDURE DIVISION USING ITEM-2. |
The following is supported instead:
LINKAGE SECTION. 01 GROUP-ITEM. 03 ITEM-1 PIC XX. 03 ITEM-2 PIC X(10). PROCEDURE DIVISION USING GROUP-ITEM. |
• The display format of the DATE-ENTRY control does not depend on settings specified by the user in the Windows Control Panel. The following styles use European conventions for time and date formatting:
TIME CENTURY-DATE LONG-DATE |
For time and date formatting conforming to American conventions, use the following properties:
DISPLAY-FORMAT "h:mm a" DISPLAY-FORMAT "MM/dd/yyyy" DISPLAY-FORMAT "EEEE, MMMM dd, yyyy" |
If your code does not currently specify any of the above styles and does not specify the DISPLAY-FORMAT property, use DISPLAY-FORMAT "M/d/yyyy". If no display format styles or properties are specified, then DISPLAY-FORMAT "dd/MM/yyyy"is the default.
• A window handle defined as PIC X(10) cannot be redefined by a USAGE HANDLE OF WINDOW item. However isCOBOL allows MODIFY on PIC X(10) as well as on USAGE HANDLE items.
• isCOBOL Reserved Words cannot be used as variable or constant names by default. In order to use them as variable or constant names, they must be treated as common words by using -rc compiler option.
• ACCEPT SYSTEM-INFORMATION FROM SYSTEM-INFO returns the complete name of the Operating System.
• File-Status codes are ANSI-2002 compliant by default. To use ANSI-85 codes instead, add the following line to the isCOBOL properties file:
iscobol.file.status=com.iscobol.io.FileStatus85 |
• Environment variables that belong to the system environment can be retrieved only when using a Java Virtual Machine version 1.5 or above.
• The CALL RUN statement creates a new thread. Environment variables and external variables are initialized to their default value.
• The STOP THREAD statement requires a YIELD statement to work correctly, otherwise, the thread will not be released. For example:
perform thread show-time handle t1. ... STOP THREAD t1. ... perform thread show-time handle t1. ... show-time. perform until 1 = 2 accept w-time from time display w-time line 2 pos 70 YIELD end-perform. |
• If your application has recursive programs, and you don’t want the data shared between different copies of the same program, add the following line to your configuration file:
iscobol.recursion_data_global=False |
• The FOR ANY THREAD clause in WAIT statement is not supported.
• The syntax "-D" at the beginning of a physical file name is not supported.
• The syntax "-Q" at the beginning of a physical file name doesn’t support CHARSET and COLS options.
• In ACUCOBOL-GT USAGE HANDLE items are automatically synchronized to offsets that are a multiple of 4. It doesn’t happen in isCOBOL. This difference might cause problems if USAGE HANDLE items are part of group items like for example record definitions, as it changes the size of the group item. In order to have USAGE HANDLE synchornized, you should change
01 my-group. ... 05 my-item USAGE HANDLE. ... |
to
01 my-group. ... 05 my-item PIC 9(9) COMP-5 SYNC. ... |
• Copybooks whose content is not terminated by a dot are not allowed. There are two solutions:
o add a dot after the last line of the copybook content, or
o use two dots to close the COPY statement (e.g. COPY "mycopy.prd"..)
• The DIVIDE statement cannot have REMAINDER without GIVING. The following statement is compiled by ACUCOBOL-GT:
DIVIDE ITEM1 INTO ITEM2 REMAINDER REM. |
In order to be compiled by isCOBOL, it must be changed to:
DIVIDE ITEM1 INTO ITEM2 GIVING FOO REMAINDER REM. |
Or you can use the REM intrinsic function:
MOVE FUNCTION REM(ITEM1, ITEM2) TO REM. |
• When a numeric data-item is used as configuration variable value in a SET ENVIRONMENT statement, Acucobol stores leading zeroes as well, isCOBOL instead stores only the numeric value, unless you compile with the -cdlz option.
• MOVE CORRESPONDING can have only one receiver data item in isCOBOL.
• The help cursor mode in help automation is not supported.
• The statement WRITE print-record AFTER ADVANCING 0 LINES doesn’t reset the caret position in isCOBOL, hence the new text is appended to the previous text instead of overwriting it.