2 COBOL Interface for Micro Focus Visual COBOL
Availability
IDM for Microsoft Windows from IDM version A.06.01.d.
2.1 Unicode Support
The COBOL Interface for Micro Focus Visual COBOL supports Unicode as character encoding. A Unicode string is represented by Micro Focus Visual COBOL as National Character, where the encoding complies with the IDM code page CP-utf16. Within Micro Focus Visual COBOL this is represented as PIC N NATIONAL.
2.1.1 Activating Unicode
The use of Unicode is activated by setting the application code page. This can be accomplished through a command line option or within the application using the DMcob_Control function:
...
WORKING-STORAGE SECTION.
01 ACTION PIC 9(4) BINARY VALUE 0.
...
PROCEDURE DIVISION
...
MOVE DMF-SetCodePage TO ACTION.
MOVE CP-utf16 TO DM-options.
CALL "DMcob_Control" USING DM-STDARGS NULL-OBJECT ACTION.
...
Notes
- COBOL compiler directives can be used to control the code page for National Character. The set application code page must match this coding. A National Character requires 2 bytes. Currently, the IDM code pages CP-utf16, CP-utf16b, CP-utf16l and CP-utfwin use a 2-byte representation.
- There are enhancements in the IDM to selectively change the code page used for individual functions of an application. This enables an incremental transition to Unicode.
2.1.2 Enhancement of CopyFiles
The copy files are defined in a way that texts can be stored either as Character or as National Character. The name of the Character entry remains. To access the National Character entry, a ‑u
has to be appended to the name.
| Character | National Character (UTF-16) |
|---|---|
DM-setsep pic X. |
DM-setsep-u pic N national. |
DM-getsep pic X. |
DM-getsep-u pic N national. |
DM-usercodepage pic X(32). |
DM-usercodepage-u pic N(32) national. |
DM-value-string pic X(80). |
DM-value-string-u pic N(80) national. |
DM-va-value-string pic X(80). |
DM-va-value-string-u pic N(80) national. |
For the following structure elements of the ValueRecord, the length or size is defined as the number of characters, not of bytes:
DM-value-string-putlenDM-value-string-getlenDM-value-string-size
The same applies to all other structures based on the ValueRecord.
Note
The IDM reads or writes the respective values based on the currently valid application code page.
2.1.3 Call Parameters of COBOL Functions
For all texts either Character or National Character can be used. The IDM interprets the text according to the currently valid application code page. The length specification refers to the number of characters, not of bytes. This applies both to the IDM interface functions as well as to the COBOL functions called by the IDM. It is important that the currently used application code page complies with the text definition.
2.1.4 Functions with Records as Parameters
For functions with record objects as parameters, the pidm application creates a copy file by means of the command line option +writetrampolin. In order not to interfere with existing applications, these copy files are created without support for National Character by default. Support for it has to be explicitly specified by using the -mfviscob-u option instead of the COBOL compiler option -mfviscob:
pidm mydlg.dlg –mfviscob-u +writetrampolin myappl_tr
The generated copy file may then contain either character or national character. Again, the IDM will access based on the current application code page.
2.2 Data Type DT-anyvalue
The data type DT-anyvalue is supported through the POINTER data type of Micro Focus Visual COBOL.
See also
2.3 Support of Collections
The colection data types of the IDM and the related functions for (managed) IDM values (Managed DM-Values) are supported through the pointer data type (POINTER) of Micro Focus Visual COBOL.
|
DM Data Type |
Visual COBOL Data Type |
|---|---|
|
POINTER |
|
|
POINTER |
|
|
POINTER |
|
|
POINTER |
|
|
POINTER |
A Managed DM-Value is passed as pointer to Micro Focus Visual COBOL:
01 ManagedValue pointer. ENTRY "GetAnyValue" using DM-COMMON-DATA ManagedValue.
To use such a value within the DM-Value structure, the value is copied to DM-value-pointer and DM-datatype is set to DT-anyvalue.
MOVE DT-anyvalue TO DM-datatype. MOVE ManagedValue To DM-value-pointer.
2.3.1 Data Function in COBOL
With the support of the collection data types, it is also possible to implement data functions in COBOL.
See also
Chapter “Data Functions”
Chapter “Data Function Structure DM-Datafunc-Data”
Function DMcob_DataChanged
2.3.2 Structure DM-ValueIndex
This structure allows for a full-fledged index argument. It is used by the DMcob_Value* functions of the COBOL Interface for Micro Focus Visual COBOL to process the collection data types. However, the structure is available for all supported COBOL variants and is not restricted to these application areas. It is identical to the DM-Value structure.
2.3.3 Functions for Working with Collections
-
With this function a value reference managed by IDM may be manipulated. Either the entire value can be replaced or a single element value in a collection.
-
With this function a value reference managed by IDM may be manipulated. Either the entire value can be replaced or a single element value in a collection. Unlike DMcob_ValueChange, this function provides a buffer for string return values that is larger than the standard buffer.
-
Returns the number of values in a collection (without the default values). It is also possible to return the index type or the highest index value.
-
This function allows to retrieve a single element value that belongs to a defined index from collections.
-
This function allows to retrieve a single element value that belongs to a defined index from collections. Unlike DMcob_ValueGet, this function provides a buffer for string return values that is larger than the standard buffer.
-
This function queries the data type of a value managed by the IDM.
-
This function can be used to determine the corresponding index for a position in a collection.
-
With this function a value can be converted into a local or global value reference managed by the IDM. This allows the further manipulation of the value by DMcob_Value…() functions and its transfer as parameter or return value.
Support