How to debug the abap program ?

Question

how  to debug  the abap program ?Can anybody explain  me in details.

Answer 1

Hi
Debugger
This section of the ABAP Workbench documentation provides information on how to use the Debugger as a test tool for finding errors in the source code of an ABAP program.
Functional Overview
Use
The ABAP Debugger is an integrated test tool within the ABAP Workbench. You use it to check the program logic and to find errors in the source code of an ABAP program. In the Debugger, you can step through the source code of a program. The running program is interrupted after each step, allowing you to check its processing logic and the results of individual statements.
As of Release 6.10, you can also run Business Server Pages (BSP) in the debugging mode. You can also display and set breakpoints here. Business Server Pages can be displayed in the Object Navigator when you select an appropriate application under BSP Application.
Features
The Debugger provides an efficient means of identifying errors in ABAP programs. It contains the following functions:
Ways of starting the Debugger
Choosing different views
Choosing different execution options in the Debugger
Displaying source code in the Debugger
• Setting and deleting breakpoints
• Setting and deleting watchpoints
• Stopping a program at a particular statement or event
Displaying and changing field contents at runtime
Displaying ABAP Objects and references
Displaying and positioning strings
Setting and deleting database locks
Opening the ABAP Editor, or Object Navigator
System settings and runtime warnings
Starting the Debugger
There are two possible strategies for starting the Debugger in the ABAP Workbench:
By setting breakpoints then running the program
By running the program in debugging mode.
Setting Breakpoints
A breakpoint is a signal in a specific line of the program source code. This signal indicates to the ABAP runtime processor to stop the program at the relevant line and start the ABAP Debugger. A distinction is made between static and dynamic breakpoints. For further information about the different types of breakpoints and how to use them, refer to Breakpoints.
Direct Processing
You can start the Debugger without previously having set breakpoints. This is the best procedure to use when you want to test a program right from the beginning. It is also a useful procedure if you are not overly familiar with the program and therefore are not sure where best to set breakpoints. You can start the Debugger as follows:
From the Object Navigator
Select a report or transaction and choose Program ® Test ® Debugging.
From the ABAP Editor
Choose Program ® Execute ® Debugging (or the Debugging pushbutton).
From any screen
Choose System ® Utilities ® Debug ABAP.
From any screen
Enter /h in the command field.
Display Modes in the Debugger
When you are debugging a program, there are various display modes that you can use. All of the display modes have the same structure. The top part of the screen displays an extract of the program source code. The bottom part displays the information specifically available in that display mode. There are also pushbuttons on the screen allowing you to switch to the most frequently-used display modes.
Display Modes Available Using Pushbuttons
Fields
The scrollable field display contains the contents of up to eight fields. The contents of the three most important system fields are always displayed. This is the default display mode in the Debugger. See also Processing Fields
Table
Displays the contents of an internal table. This mode allows you to display and edit the entries in an internal table. See also Processing Internal Tables
Breakpoints
A scrollable display containing up to 30 breakpoints. Next to each breakpoint is a counter. You can also delete breakpoints in this display. See also Managing Dynamic Breakpoints
Watchpoints
You can set a watchpoint for a field so that the program is interrupted whenever the value of that field changes. This display mode contains a list of watchpoints, the fields and programs to which they are assigned, the current values of the fields, and the conditions upon which the watchpoint is activated. See also Setting Watchpoints
Calls
This mode displays the current sequence of events, and the sequence of calls up to the current breakpoint. The last active call is displayed at the top of the list; previous calls are listed in reverse chronological order. When an event (for example, START-OF-SELECTION) concludes, it is deleted from the display.
Overview
This mode displays the structure of the program. It lists its events, subroutines, and modules, and shows which sections belong to which events. It also displays the section currently being processed.
Settings
This mode displays the current Debugger settings. You can change the settings by selecting or deselecting various options. For further information, refer to Settings and Warnings
Other Display Modes
You can access other display modes by choosing Goto ® Display data object.
Single field
Displays the contents and technical attributes of a field.
Structured
field
Displays the components of a structure, along with their contents and attributes. If you double-click a component, the system displays detailed information for it.
Strings
Display the content and current length of the string. You can also display part of the content by means of offset and length.
Internal table
Displays the type, line numbers and contents of an internal table.
Object
Displays the structure of an ABAP Object.
For further information on these displays, refer to Displaying Attributes and Displaying ABAP Objects
Checking System Programs for Errors
To check a program or program component that is part of the ABAP Workbench (for example, the Screen Painter), you must use the system Debugger. To start the system Debugger, choose System ® Utilities ® Debug System from any screen. To stop the system Debugger, choose Debugger ® Debugging off.
Displaying Program Attributes
You can display the attributes Fixed Point Arithmetic, System Program, and Unicode Checks of the program that has just been executed by choosing Goto ® Further Information ® Program Attributes.
Restarting the Debugger
If you choose Debugging ® Restart, debugging mode is stopped and the system takes you to the initial screen of the last transaction you called. If, for example, you started an ABAP program in debugging mode from transaction SE38 (ABAP Editor), choosing Debugging ® Restart will take you back to the screen titled ABAP Editor: Initial Screen. If you want to restart the program in debugging mode, choose Debugging.
Breakpoints
Apart from direct execution of an ABAP program in the Debugger, it is also possible to start the Debugger call by the exact setting of a breakpoint. This is achieved by setting one or more of these breakpoints in the program. A breakpoint is a signal at a particular point in the program that tells the ABAP runtime processor to interrupt processing and start the Debugger. The program runs normally until the breakpoint is reached.
There is also a special kind of breakpoint called a watchpoint. When you use watchpoints, the Debugger is not activated until the contents of a particular field change. For further information, refer to Watchpoints.
Breakpoint Variants
The Debugger contains different breakpoint variants:
Static
The BREAK-POINT statement in an ABAP program. Static breakpoints are not normally user-specific. However, you can make them user-specific.
Directly-set
dynamic breakpoints
Can be set in the ABAP Editor or the Debugger. Dynamic breakpoints are always user-specific, and are deleted when you log off from the R/3 System.
Breakpoints
at statement
The Debugger stops the program directly before the specified statement is executed.
Breakpoints
at subroutine
The Debugger stops the program directly before the specified subroutine is called.
Breakpoint at function module
The Debugger stops the program directly before the specified function module is called.
Breakpoint at method
The Debugger stops the program directly before the specified method is called.
Breakpoints at system exceptions
The Debugger stops the program directly after a system exception, that is, after a runtime error has been intercepted.
Static Breakpoints
Static breakpoints are not normally user-specific. Once a user has inserted the statement BREAK-POINT or BREAK name in an ABAP program, the system always interrupts the program at that point for that user or only for the user name. This procedure is only useful in the development phase of an application, when the program execution is always to be interrupted at the same place. For further information, refer to Static Breakpoints.
In HTTP sessions, a static breakpoint is skipped if you did not set additional dynamic HTTP breakpoints in the editor of a BSP page. Instead, a corresponding system log entry is written, which can be checked using transaction SM21.
Dynamic Breakpoints
Dynamic breakpoints are user-specific. Therefore, you should use them if you only want the program to be interrupted when you run it yourself, not when it is being executed by other users. All dynamic breakpoints are deleted when you log off from the R/3 System.
Dynamic breakpoints are more flexible than static breakpoints, because you can deactivate or delete them at runtime. They have the following advantages:
You do not have to change the program code
You can set them even when the program is locked by another programmer
You can define a counter that only activates the breakpoint after it has been reached
Special dynamic breakpoints are useful when you want to interrupt a program directly before a particular ABAP statement, a subroutine, or an event, but do not know exactly where to find it in the source code. Event here is used to refer to the occurrence of a particular statement, for example, or calling up a method. Special dynamic breakpoints are user-specific. You can only set them in the Debugger. For further information, refer to Dynamic Breakpoints.
In HTTP sessions, the system stops both at static and dynamic breakpoints if a dynamic breakpoint was set in the editor of a BSP page before program execution.
Lifetime and Transfer of Breakpoints
A static breakpoint remains intact as long as the BREAK-POINT or BREAK-POINT name statement is not removed from the source code. Without saving, dynamic breakpoints only remain intact in the relevant internal session. However, they are effective during the entire user session, if they are saved by choosing Breakpoints ® Save in the ABAP Debugger. For more details on the subject of sessions and user sessions, refer to Modularization Techniques in the ABAP keyword documentation.
If you call an HTTP session during a user session, only the HTTP breakpoints are loaded when the HTTP session is started. You activate HTTP debugging in the ABAP Editor by choosing Utilities ® Settings ® HTTP Debugging. Depending on the setting, the system then displays either the HTTP or standard breakpoints in the Editor.
If you call an update session during a user session, breakpoints that were defined beforehand in the calling processing unit are copied to the new update session, where they can be displayed under Breakpoints. If, in the ABAP Debugger, you check Update Debugging under Settings and then, for example, call the update module func using CALL FUNCTION func IN UPDATE TASK, a new window is opened in which you can debug this function module in the update session. All the breakpoints that were set in the calling processing unit can also be processed here.
Breakpoints at Statements
You can use this special kind of dynamic breakpoint to interrupt a program directly before an ABAP statement is processed.
Prerequisites
You must already be running the program in the Debugger.
Procedure
To set a breakpoint at an ABAP statement:
1.Choose Breakpoint ® Breakpoint at ® Statement...
The following dialog box appears:
2.Enter the ABAP statement.
The system sets a breakpoint at all points in the program at which the ABAP statement occurs.
3.Choose ENTER.
The breakpoint applies to all lines containing the specified statement.
Result
The system confirms the breakpoint and adds it to the list in the display. When you finish your debugging session, the breakpoint is automatically deleted unless you have explicitly saved it.
Breakpoints at Subroutines
You can use this special kind of dynamic breakpoint to interrupt a program directly before a subroutine is called.
Prerequisites
You must already be running the program in the Debugger.
Procedure
To set a breakpoint for a subroutine:
Choose Breakpoint ® Breakpoint at ® Event/Subroutine.
The following dialog box then appears:
Enter the name of the subroutine before which you want to interrupt the program. By default, the Program field contains the name of the program that is currently active. The system sets a breakpoint wherever the specified subroutine occurs in the program code.
Choose ENTER.
Result
The system confirms the breakpoint. The breakpoint is added to the breakpoints displayed.
Breakpoints at Function Module
You can use this kind of dynamic breakpoint to interrupt a program directly before a function module is called.
Prerequisites
You must already be running the program in the Debugger.
Procedure
To set a breakpoint for a function module:
Choose Breakpoint ® Breakpoint at ® Function module...
The following dialog box appears:
Enter the name of the function module before which you want to interrupt the program. The system sets a breakpoint wherever the specified event, module pool, or subroutine occurs in the program code.
Choose ENTER.
Result
If you entered a valid function module name, the system confirms that the breakpoint has been set. If the function module exists in the system, the new breakpoint is added to the display list.
Breakpoints at Methods
You can use this special kind of dynamic breakpoint to interrupt a program directly before a method is called.
Prerequisites
You must be already running the program in the debugger.
Procedure
To set a breakpoint for methods:
1. Choose Breakpoint ® Breakpoint at ® Method...
The following dialog box then appears:
2. Enter the name of the method and class before which you want to interrupt the program. A breakpoint is then set each time the specified processing block appears in the source code.
3. Choose ENTER.
Result
The system confirms the breakpoint. The breakpoint is added to the list in the display.
Breakpoints at System Exceptions
You can use this special form of dynamic breakpoint to interrupt a program immediately after a runtime error has occurred.
Prerequisites
You must already be running the program in the Debugger.
Procedure
To set a breakpoint at a system exception:
Choose Breakpoint ® Breakpoint at ® System exception.
Result
The system confirms the breakpoint. The breakpoint is added to the breakpoints displayed.
When a system exception is triggered, a warning triangle appears in the line containing the statement that caused it. If you double-click the warning triangle, the internal name of the runtime error appears.
Static Breakpoints
You should only use static breakpoints during the development phase of an application. You must remove them from your program before you transport it.
Setting Breakpoints
To set a static breakpoint, use the ABAP statement BREAK-POINT . Place the breakpoint in the line at which you want to interrupt the program.
program RSDEBUG_01.
if SY-SUBRC 0.
break-point.
endif.
When you run the program, the runtime processor interrupts it when the breakpoints occur. You can number your breakpoints to make them easier to identify ( BREAK-POINT 1, BREAK-POINT 2 …).
Static breakpoints are not normally user-specific. The program is, therefore, always interrupted as soon as the runtime processor reaches the line containing the breakpoint. The program is interrupted regardless of the user who executes it.
However, you can set user-specific static breakpoints using the BREAK statement followed by your user name. For example, if you use the statement BREAK SMITH , the program is only interrupted when user Smith runs it. Although user-specific breakpoints appear in the program code, they are not active when other users run the program. You should, however, be careful if an application is being used by several users with the same name.
Deleting Breakpoints
Since static breakpoints apply to all users, you must remove them from the program once you have finished testing it. In the ABAP Editor, you can find breakpoints quickly by choosing Utilities ® Global search. You can also use the Extended Program Check to find them.
If you do not remove static breakpoints from your program, they will be transported to your production system. This could cause serious problems in the production system.
Dynamic Breakpoints
You can set up to 30 dynamic breakpoints without changing the program code. Dynamic breakpoints can be set either in the ABAP Editor or directly in the Debugger.
Setting Dynamic Breakpoints in the ABAP Editor
You can set dynamic breakpoints in the ABAP Editor regardless of whether you are in display or change mode. You can also set breakpoints directly from within the Debugger at runtime. To set a dynamic breakpoint in the ABAP Editor:
Position the cursor on the line of the source code at which you want to set the breakpoint.
Choose Utilities ® Breakpoints ® Set or the Stop icon. The system confirms that the breakpoint has been set.
To display a list of all dynamic breakpoints in a program, choose Utilities ® Breakpoints ® Display. You can use this list to navigate to a particular breakpoint or to delete one or more breakpoints from the program.
Setting Dynamic Breakpoints in Debugging Mode
To set a dynamic breakpoint in the Debugger:
Position the cursor on the line in which you want to set the breakpoint.
Select the line by double-clicking it or choosing Breakpoint ® Set/delete.
The system sets the breakpoint, and displays a small stop sign to the left of the relevant line. If the line already contained a breakpoint, it is deleted.
When you finish your debugging session, the breakpoint is automatically deleted unless you have explicitly saved it.
Saving Breakpoints
If you want to leave the Debugger temporarily, you can save your dynamic breakpoints so that they are still active when you return to the Debugger within the same terminal session.
To save the breakpoints that you have set in the Debugger:
Choose Breakpoint ® Save.
The system saves all of the breakpoints that you have set in the current program. These breakpoints will remain active until you either explicitly delete them or log off from the system.
You can also delete breakpoints that you have saved:
By deleting individual breakpoints from the display and then saving again. In this case, only your selected breakpoints will be deleted.
By choosing Breakpoint ® Delete all. In this case, the system deletes all dynamic breakpoints.
Managing Dynamic Breakpoints
The ABAP Debugger provides a convenient user interface for managing breakpoints. To open the breakpoint display, choose Breakpoints, or, from the menu, Goto ® Control debugging ® Breakpoints.
Example
Functions
This display mode contains the following functions for breakpoints:
Breakpoint Display
The scrollable breakpoint display contains up to 30 dynamic breakpoints. For breakpoints that you set directly, the program name and line number at which the breakpoint occurs are displayed. For special breakpoint forms, the list displays the statements, events, subroutines, and module calls at which the relevant breakpoints are set.
Counter
In the breakpoint display, you can specify a counter. When you use a counter, the breakpoint is not activated until it has been reached a specified number of times. For example, if you enter 5 for the counter, the breakpoint is not activated until it is reached for the fifth time. After the breakpoint has been activated, it remains so, and the counter no longer appears in the breakpoint display.
Deleting Breakpoints
Position the cursor on the breakpoint that you want to delete, and either double-click the line or choose Breakpoint ® Set/delete. To delete all breakpoints, choose Breakpoint ® Delete all.
Activating and Deactivating Breakpoints
Position the cursor on the breakpoint that you want to activate or deactivate and choose Breakpoint ® Activate/deactivate.
Watchpoints
Like a breakpoint, a watchpoint is an indicator in a program that tells the ABAP runtime processor to interrupt the program at a particular point. Unlike breakpoints, however, watchpoints are not activated until the contents of a specified field change. Watchpoints, like dynamic breakpoints, are user-specific, and so do not affect other users running the same program. You can only define watchpoints in the Debugger.
Use
You set watchpoints in the Debugger to monitor the contents of specific fields. They inform you when the value of a field changes. When the value changes, the Debugger interrupts the program.
Features
You can set up to five watchpoints in a program.
See also Setting Watchpoints.
You can also specify the conditions on which a watchpoint is to become active.
You can specify logical conditions between up to five conditional watchpoints.
See Specifying a Logical Expression.
You can define watchpoints as either local or global. If you define a global watchpoint, it is active in all called programs. Local watchpoints are only active in the specified program.
You can change and delete watchpoints.
See Changing Watchpoints.
You can use watchpoints to display changes to the references of strings, data and object references, and internal tables.
See Memory Monitoring with Watchpoints
Setting Watchpoints
If you want to interrupt a program when the contents of a field or structure change, use a watchpoint. You can set up to five watchpoints, including watchpoints for strings.
A watchpoint can be either local or global. Local watchpoints are only valid in the specified program. Global watchpoints are valid in the specified program, and also in all the other programs it calls.
Procedure
To set a watchpoint, start the Debugger and proceed as follows:
Choose Breakpoint ® Create watchpoint or the corresponding pushbutton. The Create Watchpoint dialog box appears:
Decide whether you want to set a local or global watchpoint.
Enter the program and the name of the field for which you want to set the watchpoint. In the Program field, the name of the program currently running is always defaulted.
If you want your watchpoint to be activated each time the contents of the field change, the definition is now complete, and you can return to the Debugger by pressing ENTER .
To create a conditional watchpoint, that is only activated when a particular situation arises, choose one of the following relational operators.
Operator
Meaning
<
Less than
<=
Less than or equal
=
Equal
<>
Not equal
=
Greater than or equal
Greater than
You can use the Comparison field option to specify whether the comparison is to be carried out with a value that you specify or with the contents of another field. Depending on your choice from step 6, enter a value or a field for the comparison.
Result
The system confirms the watchpoint and adds it to the list in the display. When you finish your debugging session, the watchpoint is automatically deleted unless you have explicitly saved it.
Specifying Logical Links
If you have more than one conditional watchpoint, you can specify a logical link between them:
OR
Only one of the specified conditions must be met
AND
All of the conditions must be met.
Changing Watchpoints
Choose Goto ® Control debugging ® Watchpoints or the Watchpoints pushbutton to display the watchpoint list. The following dialog box appears:
Choose the pencil icon in the line containing the watchpoint you want to change.
Change the watchpoint attributes in the Create/Change Watchpoint.
Choose ENTER .
Deleting Watchpoints
You cannot delete watchpoints by choosing Breakpoint ® Delete or Breakpoint ® Deactivate/activate. Instead, proceed as follows:
Choose Goto ® Control debugging ® Watchpoints or the Watchpoints pushbutton to display the watchpoint list.
Choose the trashcan icon in the line containing the watchpoint you want to delete.
Memory Monitoring with Watchpoints
You can use watchpoints to display changes to the references of strings, data and object references, and internal tables. By placing an ampersand (&) in front of the object name, you can display the reference in question in hexadecimal format. With internal tables, you can also display the table header by placing an asterisk (*) at the beginning of the name.
&objectname
Displays the references of strings, internal tables as well as data and object references
*itab
Displays the table header of the internal table itab
Example
If a watchpoint is set for the object in question at runtime, the program is stopped as soon as the reference is changed. A short dump can be intercepted in this way to stop the program being terminated when the memory is overwritten.
Analyzing Source Code
The Debugger contains an extensive range of functions that help you to analyze the source code of a program. You can step through the source code of a program in four different ways. For further information, refer to Stepping Through the Source Code
For information about functions within the source code display, see Displaying the Source Code
There are also different display modes that provide various information and display the contents of individual fields, tables, and so on:
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