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Debugging
Program ... . Breakpoint ... .
ABAP/4 Editor
ABAP/4
Debugger
Debugging
Program B170D051
Breakpoints
Object List
Development object ... ... ...
. . .
Test/execute
. . .
Any screen
... ... ... System Help
. . .
Utilities
. . .. . .
Debug ABAP/4
. . ./h
Branching to Debugging Mode
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Debugging Mode
PROGRAM B170D051.
DATA: DIFF TYPE P,...
COMPUTE DATE_1 = SY-DATUM.
..
.
Execute Single step Execute Continue Table
DATE_1 00000000
SY-DATUM 19940223
Variables
X R
R
R
R
R
O S V F T P
View pushbuttons
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The Most Important Debugging Functions
Single Step Processes the next program line.
Execute In contrast to the single step, executes
all processing steps belonging to one line.
Continue
Table
Processing continues until the next breakpoint oruntil the end of the program.
Displays the contents of internal tables.
Breakpoint With the functions of this menu you
define breakpoints.Editor You go to the ABAP/4 editor.
Hexadecimal-
display
Data contents can be displayed in hexedecimal format.
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Setting Breakpoints
Menu
Keyword
Utilities-> Breakpoints
BREAK-POINT
Line selection (double-click)
Menu: Breakpoint
-> Set/delete
Goto
-> Breakpoints
ABAP/4 Editor
Debugging mode
11
22
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Other Debugger Features
Replace Field ContentsReplace Field Contents
Display/Change Internal Table EntriesDisplay/Change Internal Table Entries
Display Output ListDisplay Output List
Switch to ABAP/4 EditorSwitch to ABAP/4 Editor
Database ReleaseDatabase Release
Activate/Deactivate BreakpointsActivate/Deactivate Breakpoints
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A detailed explanation of ABAP/4 Debugging.
The slides for the ABAP/4 Development Workbenchs on lineDebuggers Contain the following topics,
Online debugging tools.Starting the debuggerThe debuggers six viewsUsing break pointsSetting static break pointsSetting dynamic break pointsSetting watch pointsSetting breakpoints at keywords or eventsDeleting and deactivating breakpointsStepping through program codes
Displaying field contents
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Displaying Internal tablesDisplaying ABAP/4 listsReplacing field values at runtimeChanging internal tables at runtimeSwitching to the ABAP/4 EditorReleasing the database during debugging
Online debugging tools : A review
The ABAP/4 Debugger lets you stop a program during runtime and
examine the flow and results of each statement during
execution.Stepping through a program with the debugger helps you to
detect and correct errors in your code.This documentation is designed for
developers new to the Workbenchs debugging facilities or for those whowant to learn the tool to use the tool more effectively.
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After working through this slides , you should be able to debugg both
familiar and unfamiliar programs effectively. With this slides, you will
learn how to
Switch on the debugger
Set and delete static and dynamic break points.
Set watch points
Stop a program at specific key words or events or when a field contentschange.
Continue processing after an interrupt.
Display field contents during runtime.
Display the contents of an internal table.
Change field contents for testing purposes.Change the contents of an internal table.
Display and use debuggers six different views.
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Debugging Strategies form within ABAP/4 Development Work bench. We
can set breakpoints in a program and then start the program within the
Debugger.Alternatively, we can run the program in the debugger without
any breakpoints.
A Breakpoint is a signal within a line of code that tells the ABAP/4runtime processor to interrupt the program at the line.Setting break
points is a good strategy if we want to examine a program:
After the system has already processed certain events
Just before a specific event is carried out
By skipping quickly to a specific routines or calls
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Starting the Debugger
On running a program in the debugging mode the following steps can be
followed.
In the object browser ,
Select a report or transaction.
Choose debugging in the ABAP/4 editor initial screen
Choose ProgramExecuteDebugging or choose debugging.From any screen , Choose SystemUtilitiesDebug ABAP/4.Debuggers six views
A debugger selects between six different views , by selecting appropriateview name in debuggers menu.
Or by pressing small push-buttons at right corner of each debugging
screen.
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These buttons has following specific meaning.
O Overview - Displays the structure of the program to be
debugged.S Call stack Displays an active event chain and the call
sequence up to the current breakpoint.V Variables Displays the contents up to four fields or field
strings.F Field display Displays the fields content and technical
characteristics.T Table Display Displays the content of an internal table.P Programs Displays all programs needed to run the report
or transaction to be debugged, including
system program
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Structure of the Debugging view.
Each debugging view has the same structure. The top half of the screen
displays a portion of the programs source code. The lower half shows
information specific to that particular view .Next to the Line Display
appears two push buttons + sign and sign , to scroll through the
program code.
The line currently ready for processing is indicated by >.A small stopsign appears to the left of each dynamic break point .A red light appears
at the bottom of screen after reaching a break point.
If no breakpoints are present, the light is green.
Using Breakpoints
A breakpoint is a signal within a programs code , which tells the ABAP/4
processor to interrupt the program at a particular point. The type of
breakpoint depends on the purpose of debugging.
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Following are the types of breakpoints.
Static
These are user independent , set directly into a programs code with the
editor. User dependent breakpoints also is possible.
Dynamic
Set within the ABAP/4 debugger or editor. This type is invisible when theprogram is displayed in the editor.
Watch points
Set within the ABAP/4 debugger .Watch points are field-specific. This is
used to observe changes to a particular field .The debugger interruptsthe program when fields content change. Only one watch point is
possible at a time.
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Key word or event breakpoints
Set within the ABAP/4 debugger. The debugger interrupts the program
when the ABAP/4 processor comes in contact with a specific key word or
event in programs code.
When a static breakpoint is used?
Static break point are generally user-independent. On setting this
breakpoint , every use who executes the program encounters the
breakpoint. This is used when several developers are working in thesame program, and all wants to the program to interrupt at the same
place during execution.
These breakpoints are visible in the programs code.
When a dynamic breakpoint is used?Dynamic break point is user-specific. If we want to interrupt a
program when we execute and while others are running, we use dynamic
break-point.
Dynamic breakpoints are more flexible than static breakpoint , they
can be removed or deactivated during runtime.
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When to use watch points.
We can set watchpoints only from within the debugger.They are useful ifwe want to interrupt a program only when there is a change in a particular
field or a field string. We can set and remove watch points as
Needed .This , as dynamic breakpoint , does not disturb the other users
of the same program.
When to use breakpoints at Keywords or Events.
From within debugger , we can allocate breakpoint for specific ABAP/4
keywords or program events.
This is useful if we do not know exactly where a key word or event occurs
, but still want the program to be interrupted just before the command orevent is carried out.
Setting Static Breakpoints.
To set a static break point use BREAK-POINT keyword.
Place the break point on the line where to interrupt the program:
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REPORT RSDEBUG1
CHECK ACCOUNT
IF SY-SUBRC NE 0.
BREAK-POINT.
ENDIF.
.
When we start the report , ABAP/4 interrupts the processing at the breakpoint.
We can number breakpoints like BREAK-POINT1 ,BREAK-POINT2..for
easier identification.
Removing Breakpoints.It is necessary to remove the breakpoints after debugging .Use function
Utilities Global search to help in locating break-points in largerprograms. It is necessary to remove breakpoints since it may cause
serious disruptions in productive process.
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Setting Dynamic Breakpoints
We can set dynamic breakpoint , without changing the programs code.
Following are the steps to set a breakpoint in ABAP/4 Editor.
Place the cursor on the line where to position the breakpoint.
Choose Utilities BreakpointSet.A display of all breakpoints in a program can be obtained by selecting
UtilitiesBreakpointsDisplay function.
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Setting Watchpoints.
A watch point is set to interrupt a program when the contents of a
specific field or a string change.
Following are the steps to set a watch point.
Locate the field in the code.
Place the cursor directly on the field.Choose F for Field display. The debugger displays the field
display view.The field view displays the fields content and offers detailed
information about its technical nature.Set the watch point checkbox to the right of fields name.Continue executing the program by choosing Continue.
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Displaying the current watchpoint.
Choose Goto Breakpoints .The system displays the breakpointoverview screen.
Setting Breakpoints at keywords or Events.
If we want to interrupt the program directly before a certain keyword,
event or a subroutine , we use this facility.We can achieve this with the following steps.
Choose either BreakpointBreakpoint atAt event/FORM orBreakpointBreakpoint atAt key word.
The system will display a small screen prompting to enter name
event or keyword.
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The system will set a breakpoint each time the key word , event
for subroutine appears in the program.For break point in form routines , it is possible to access the
current program , not external subroutine calls.Choose OK.
To interrupt a program whenever the system return is not equal
to
zero, select Breakpoint Breakpoint atAt SY-SUBRC0.
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Deleting and Deactivating Breakpoints.
During the debugging process, the breakpoints in the earlier run need to
be ignored.In case of static dynamic breakpoints it is flexible during
runtime. In case of dynamic breakpoints, there are more possibilities of
controlling it ,than static breakpoints.
Deactivating Static Breakpoints.
Sataic breakpoints are hard coded directly into program using BREAK-POINT or BREAK. This is deactivated by deleting the BREAK-POINT or
BREAK keywords.
Breakpoints and breakpoints at keywords and events.
Dynamic breakpoint are not written directly in the programs code. It can
be deleted or temporarily deactivated and reactivate breakpoints at
keywords or events as the same way as dynamic breakpoints.
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Stepping through program code.
From within the debugger several options for stepping through the
program.
Single step : Execute a program statement by statement. If single step is
chosen while on a line that calls a FORM routine , for example the next
mouse click carries to the called routine.After stepping the way through
the subroutine, returns to the line of code directly following thesubroutine call.
Execute : Process a program line by line. On choosing Execute while on
a line, that calls a FORM routine, the debugger executes the subroutine
subroutine and halts at the line of code directly following the call.Thus this skips over the lines of the subroutine itself.
Continue Processes the program up to the next active dynamic or static
break point. If no further breakpoints exists, the system executes the
report in its entirety without stopping.
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To delete a dynamic breakpoint , place the cursor in a line and choose
BreakpointSet/Delete all.Deleting this breakpoint is also possible by double clicking theappropriate line.
From within the editor, deleting the dynamic breakpoint is done by the
following steps.
Choose UtilitiesBreakpointsDisplay.The System will list all the breakpoints.Select one or more breakpoint.Choose Delete individual .
Temporary deleting of Dynamic breakpoint is possible by selecting the
appropriate line and select Breakpoint Deactivate/Activate.
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Deleting Watchpoints.
Watch points are special break points set for specific fields. Only one
watch can be set at a time.
To remove a watch point , the following steps will do.
Choose F to enter the field display view.
Choose Breakpoint Delete/Set watchpoint or turn the Watchpointcheckbox off.
Displaying the Location of breakpoints.
Select Goto Breakpoints to get an overview of all existing breakpointsin a programs code.From the breakpoint display , it is possible to set or delete individual
breakpoints.
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Return Returns the debugger to where a calling program resumes
control.Can be used from within a subroutine call.
Displaying the field contents.
During the course of debugging , display of the contents of the critical
fields used in the program.To display the field view contents, enter the
variable view.This is the default Debugger view. It is possible to reach thevariable view from any of the Debuggers other five views by choosing V.
Display of the contents up to four fields or field strings possible can be
done. We can enter the field names directly in the spaces provided or
double click the field in the code display and the system lists it as avariable automatically.
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We can use the variable screen to display the contents of any system field
or all field that a program references. Also the debugger to display fields
defined in the ABAP/4 Dictionary can be used.
To display the contents of dictionary fields, we must define relevant tablein the TABLES statement of the current program.
Additionally the contents of the fields from external programs can be
displayed.
For this we need to place the name of the external program in brackets infront of the field name.
We can display the contents of the fields in either edited or hexadecimal
format. To switch to the hexadecimal display, choose the small push-
button directly following the value field. When the field is in hexadecimal,an X appears on this push-button. Other wise , the button is blank.
We can always display a whole field string. To show only certain
sections, specify the appropriate offset and length. In this case we can
switch to the hexadecimal display in order to interpret packed values.
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Field contents and the most important attributes of a selected field or
field string can also be displayed in the special field view screen.
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Displaying Internal tables.
Within the debugger , we can display the contents of an internal table by
choosing the Table function.
The system displays the Table view. Specify a table name in the Internal
table field or double click on the table. If the internal table contains a
header line, this line appears before the actual table contents and is
marked in the display by >>>>>>>.The table rows are numbered. We can
scroll through the table display using the Index field or the scroll icons. Ifwe want to see those parts of the tables that are not visible on the left or
right of the screen , use the push buttons for horizontal scrolling or
simply shift the title bar of the table.
Using the column header line, we can also change the sequence of thefields we want to see. If we remove a field name from the column header
line, then the system deletes the field from the display. If we specify an
incorrect field name, the system displays a string of question marks.
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If the space you leave to display a field is too small , the system
truncates the display and indiates this by a
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Replacing fields at Runtime.
While we are debugging a program , we might want to change the content
of specific fields to influence our programs flow. If error analysis revealsthat a field contains a wrong value , for example , we can replace the
faulty value at run time to determine if the program then runs correctly.
We can change the values of all fields , database tables (with offset) and
internal tables referenced in a report . If we alter the values of databasefields , we do not change them in the database itself , but only in the work
area ABAP/4 provides for one run of the report .The system displays an
appropriate message if any format errors occur.
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To replace the value , we can do the following steps.
1.Go to the variable display screen.
This is the Debuggers default view.2.Double click on a variable to place it in the variables display.
3.Enter a new value in the second column of the variable display next to
the appropriate field.
4.Choose the R (Replace)button.
ABAP/4 writes the new value back to the program field or fields and the
system notes the change in the
system log. If we forget to click on the R push-button , the system
ignores the values we entered.
Note: ABAP/4 accepts our entries in the contents column exactly as we
specified them. You need to pay special attention to the correct format.(
Upper or lower case , right justified output with packed numbers).
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Changing Internal Tables at Runtime
The debugger allows to manipulate the contents of an internal table
during runtime. We can delete, edit or add a row to an internal table.
Deleting a row
To delete an entry from an internal table:
1. Go to the table display screen2. Enter the table name in the internal table field.
3. Choose Enter.
The system displays the tables contents.
4.Place the cursor on the line you wish to remove from the table.5.Choose Delete.
The line disappears from the table and the system adjusts the line
numbering accordingly.
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Editing a row
The functions Modify , Insert and append are field-specific in the
Debugger and can be carried out only one field at a time.For example ,If we want to edit the following line:
LH001 FRANKFURT NEWYORK 145400 400 X,
we first need to decide which field to change.
Then the following steps must be done.
1.Place the cursor on the row and field we want to edit.
2.Choose Modify.
3.Enter a new value for the field.
4.Choose Enter.
The system updates the line and displays the new contents in the table.
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.Adding a Row
We can add a new row to an internal table by using either Append or the
Insert function. Append places the new line at the end of the table.
Insert lets us to position the line anywhere.
To add a new row to the end of the table , the following steps will do.
1.Choose append.
2.Enter a value for the first field in the line.
3.Choose Enter.
The system adds a line to the table and fills in the first field.
4.Enter the remaining fields of the line by following the procedure forediting a row as described above.
To insert a new line anywhere in the internal table ,position the cursor on
the line directly following the line where we want the new row to appear.
Then ,Choose Insert button and proceed as we want to append the line.
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.Switching to the ABAP/4 Editor
We can switch from the Debugger to ABAP/4 Editor at any time. If we
discover a program error during the debugging process , for example,wecan enter the ABAP/4 Editor to immediately correct the error in the
programs code. We can also switch back to the editor in order to set new
static break-points.
After we set static breakpoints in the editor,they are not active in the
debugger when we switch back.We must re-generate the program.Thenthe breakpoints appear in the debugger.
To return to the Editor for the program currently being debugged ,
Select Development-->ABAP/4 Editor.
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.Releasing the Database during debugging
During debugging, the system normally suppresses the COMMIT
statement. The COMMIT statement marks the end of a logical unit ofwork(LUW).
As a result , the system locks up the database for the course of that
debugging session.
If we want to temporarily stop the program but do not want to end
session,we should release the database that in use.If we forget to release
this lock,no other user is able to modify data until we complete the test.To
release the database explicitly during break in testing , choose
Debugging -->Database -->Commit.
To undo all changes made in the database since the last COMMIT selectDebugging-->Database-->Rollback.
Debugging
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