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Static Call in COBOL |
In COBOL programming, the static call in COBOL is a powerful feature that allows programs to invoke subprograms or perform subprogram calls. The static call statement in COBOL provides a way to execute a specific subprogram without the need for dynamic resolution at runtime.
This article will provide a clear and concise overview of static calls in COBOL, including their performance considerations, implementation examples, and best practices.
Static Call in COBOL.
The COBOL static call is a mechanism that enables the program to directly invoke a subprogram without any runtime resolution. Unlike dynamic calls, which require the program to determine the subprogram to be called at runtime, static calls are resolved at compile time. This means that the program knows the target subprogram and its location in memory before execution.
The static call statement in COBOL follows the syntax:
CALL 'subprogram-name' USING parameters
Here, 'subprogram-name' is the name of the subprogram to be called, and parameters are the data items passed to the subprogram. The subprogram can be another COBOL program or a COBOL subroutine.
Example: CALL "EMP002" USING RECORD-1
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| COBOL Static Call. |
Static Call Performance Considerations
When using static calls in COBOL, there are several performance considerations to keep in mind:
- Compile-time resolution: Static calls are resolved at compile time, which means that the program needs to be recompiled whenever the target subprogram changes. This can result in longer development cycles and increased maintenance efforts.
- Efficiency: Dynamic calls are less efficient than static calls because they require runtime resolution, while the program can directly jump to the exact location of the subprogram in static calls.
- Memory usage: Static calls require the subprogram to be loaded into memory at compile time. This can result in increased memory usage, especially if the program has multiple static calls to different subprograms.
Considering these performance considerations, it is important to carefully evaluate the use of static calls in COBOL applications. While static calls can improve performance, they may not be suitable for all scenarios.
How to Use Static Call in COBOL.
To use static calls effectively in COBOL, consider the following best practices:
- Identify appropriate scenarios: Static calls are best suited for situations where the target subprogram is unlikely to change frequently. If the subprogram is expected to change frequently or if dynamic resolution is required, dynamic calls may be more appropriate.
- Organize subprograms: Group related subprograms together to minimize the number of static calls and reduce memory usage. This can improve the overall performance of the COBOL application.
- Document dependencies: Clearly document the dependencies between the main program and the subprograms. This will help in understanding the flow of the program and identifying the impact of any changes in the subprograms.
- Perform thorough testing: Before deploying the COBOL application, thoroughly test the static calls to ensure they are functioning as expected. This includes verifying the correct passing of parameters and validating the behavior of the subprograms.
COBOL Static Call Examples and Best Practices
Let's look at a couple of examples to illustrate the use of static calls in COBOL:
IDENTIFICATION DIVISION.
PROGRAM-ID. MAIN-PROGRAM.
*
* Main program that will call two subprograms.
*
DATA DIVISION.
WORKING-STORAGE SECTION.
01 PARAM-1 PIC X(10) VALUE 'Hello'.
01 PARAM-2 PIC X(10) VALUE 'World'.
PROCEDURE DIVISION.
MAIN-PROCEDURE.
CALL 'SUBPROGRAM-A' USING PARAM-1, PARAM-2.
CALL 'SUBPROGRAM-B' USING PARAM-1, PARAM-2.
STOP RUN.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUBPROGRAM-A.
*
* Subprogram A called by Main-program.
*
DATA DIVISION.
WORKING-STORAGE SECTION.
01 PARAM-1 PIC X(10).
01 PARAM-2 PIC X(10).
PROCEDURE DIVISION USING PARAM-1, PARAM-2.
DISPLAY 'Subprogram A: ' PARAM-1 ' ' PARAM-2.
EXIT PROGRAM.
IDENTIFICATION DIVISION.
PROGRAM-ID. SUBPROGRAM-B.
*
* Subprogram B called by Main-program.
*
DATA DIVISION.
WORKING-STORAGE SECTION.
01 PARAM-1 PIC X(10).
01 PARAM-2 PIC X(10).
PROCEDURE DIVISION USING PARAM-1, PARAM-2.
DISPLAY 'Subprogram B: ' PARAM-1 ' ' PARAM-2.
EXIT PROGRAM.
In this example, the main program calls two subprograms, SUBPROGRAM-A and SUBPROGRAM-B, using static calls. The parameters PARAM-1 and PARAM-2 are passed to the subprograms, which display the values received.
By following these examples and best practices, you can effectively implement static calls in your COBOL applications, improving performance and maintaining code organization.
Conclusion.
The COBOL static call is a valuable feature that allows programs to directly invoke subprograms without runtime resolution. By understanding the performance considerations, best practices, and examples provided in this article, you can effectively utilize static calls in your COBOL applications. Remember to carefully evaluate the suitability of static calls for each scenario and consider the impact on development cycles, efficiency, and memory usage.
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Good Information.
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