Serious Global Variable Bug in Crosstabs

Global variables should have its scope within a main report. However if you use formulas particularly that keeps a running total within a crosstab that utilises global variables you find that once the crosstab continues over a page break the values in the global variables are lost and reset back to zero.
A simple test would be to add the following VB formula in a summary field (as referred to in the above article) for the u201CDisplay Stringu201D property value
WhilePrintingRecords
Global Test as Currency
Test = Test + 1
formula = Totext(Test,0)
This is a bug in all versions of Crystal Report right up to 2008.
Whenever a cross-tab goes over a page break it resets any variables it is using, even though the variable is global. The reset goes back to the value of the variable at the beginning of the split section. Usually this means a reset to zero. However in cases where the variable already has a value before the cross-tab section starts, it resets to that value.
There must be a bug or design flaw in the way the split pieces of a cross-tab are processed.

Crosstab is not an ideal solution for a detailed or complex reports as it has many flaws. I myself ditched crosstab and used crosstab Mock to create my reports.
Regards
Jehanzeb

Similar Messages

What are the best practices to use GLOBAL Variables

Hi,
Please guide how Global Variables can be declared and how they can be initialized.
Further please guide what are the impacts of Global Variables(if any) on the memory of CLIENT or SERVER, if they are not initialized or freed up after usage.
Thanks.
Regards.

spilgrim wrote:
My preference is not to use them and to use parameters or package variables. There is not real control on globals so you can end up with an applicatios that has lots of them that are only used once but persist for the user session.I second that. I don't know how often I searched for bugs caused by typos in the names of global variables. Plus the fact that they are only of datatype VARCHAR2. If you are using share_library_data you could also use Package globals in a forms library to share data between called and calling forms. Or you could use a database package...
cheers

Copying Global variables

Is there any easy way to copy a group of global variable from one job to another? I know I can insert the global variables one at a time but there must be a quicker way????

Hi Richard,
You might be interested in a new feature in the 12.0 release of Data Integrator (it's built on the Data Services XI 3.0 platform). The feature is called "substitution variables", and allows you to have a single set of variables for a runtime environment. They are static in nature (meaning you cannot change their value after you launch a job) but you can have different configurations of variable assignments. You control all of this using system configurations -- it's a lot like using datastore configurations with system configurations today, except that you can define sets of substitution variable values to go along with a specific system configuration.
You may want to talk to your account manager about migrating your license to an XI 3.0 license. Also, the first service pack for 12.x will be released soon (Septemberish?), which is a good indication that the tool is ready for serious production usage.
Thanks,
~Scott

PLSQL: Changing in parameter thru assignment to global variable???

Hi there!
On 10gR2 (10.2.0.3) the following PL/SQL block
declare
glob_val pls_integer := 2;
procedure test_p(x in pls_integer) is
begin
dbms_output.put_line(x);
glob_val := 3;
dbms_output.put_line(x);
end test_p;
begin
dbms_output.enable;
test_p((glob_val));
end;
appears to change the value of the in-parameter x by an assignment to the
global variable glob_val. To verify, just check the dbms_output generated.
This is completely unexpected behaviour, and contrary to my understanding of
PL/SQL's parameter passing mechanisms. If this was the intended behaviour
in 10.2 it would definitely break tons of existing PL/SQL code.
Has anyone run into this problem before? Is this a bug? Is there a workaround
available? Any ideas??
All the best
Michael

Sorry, I cannot accept that statement.
According to the PL/SQL user's guide
<QUOTE>
Using the IN Mode
An IN parameter lets you pass values to the subprogram being called. Inside the subprogram, an IN parameter acts like a constant. It cannot be assigned a value.
You can pass a constant, literal, initialized variable, or expression as an IN parameter.
IN parameters can be initialized to default values, which are used if those parameters are omitted from the subprogram call. For more information, see "Using Default Values for Subprogram Parameters".
</QUOTE>
IN-Parameter were not passed by reference in former versions of PL/SQL.
You may notice that you cannot assign to an in-parameter either; an attempt
to do that will just produce the error PLS-00363.

Program units (Package) as global variable

Hi all,
Report 10g, generate PDF on the web.
I need to manage some informations as rowtype.
So, I defined a program unit as Package Spec VAR and defined v1 tablename%rowtype. When fired the trigger After Parameter Form run a procedure that populate the VAR.v1 and so I can use this information inside the column formula or format trigger without read the table many times.
I try on client / server and all is ok.
I try on the web and the package spec not work good. Exist some rule or bug about it?
I try to move the package on the DB as Stored Procedure and so the report is ok.
Thank you in advance.

But in report builder is it possible to use global variable define as rowtype?
I have some doubts about it.
About my problem I want add an example to understand better the situation:
As program unit I defined:
PACKAGE VAR IS
vTab0001 tab0001%rowtype;
END;
FUNCTION TAB0001_GET (pCom number) RETURN tab0001%rowtype IS
vTab0001rec tab0001%rowtype;
BEGIN
Select *
into vTab0001rec
from tab0001
where t0001soc = pCom;
return (vTab0001rec);
Exception when others Then
return (null);
END;
About the After Parameter Form trigger:
var.vTab0001 := tab0001_get(:company_code);
With the srw.message(12345, var.vTab0001.t0001soc) check the value in all the report.
In client/server all it is ok.
In web I received the error
REP-0069: Internal error
REP-57054: In-process job terminated:Terminated with error:
REP-1418: 'cf_1formula': Passed null arguments to SRW.MESSAGE.
So, I have the evidence that the var.vTab0001.t0001soc is null.
Can you help me to find a way?
Is there someone that had this case in report builder?

Control references vs. global variables

I guess my question centers on the appropriate application of control references.
I am writing a complex program that has a state machine at the top level, and, for one frame of the state machine, a while loop containing a couple subVIs, each of which contains many subVIs. The lower-level subVIs are affected by buttons on the top-level VI. Information from the lower-level VIs must be shown on the top-level front panel within the loop. My question is: what is the best way to do this?
(I have a previous version of the program that I wrote that keeps just about everything on the top level so that I can update the front panel, but this is not at all modular.
In addition, I considered breaking things up into more than on
e front panel, but this doesn't seem to be a good option for this section of this program.)
Last week I read about control references, and decided that this could be the way to deal with this issue. I have not worked with them before, so I want to know: Are control references an appropriate solution for this issue? Is it good programming practice to use them, especially to update data on charts and graphs? How do they compare programming-wise and efficiency-wise to global variables?
Global variables are another solution, I think, but I would have way too many variables to update. I think the advantage with global variables is that one could just insert a global variable in a subVI and not have to wire it up through the different subVI levels, which one would have to do (I think) with control references.
Can you offer any advice?
Thanks!

Paul,
The actual implementation of the solution is up to you. This is indeed a complex question.
I would offer the following advice:
On globals:
Try to avoid them. I try to restrict the use of globals to unidirectional. If you have ever dealt with a race condition, you will know why. Mistakes are often made with globals, and they are quite apt to become the biggest source of bugs in a program, especially in one as large and/or complex as your appears to be. If you must use globals, try using a shift register, or LabVIEW 2 style global instead. Basically, you use an unitialized shift register with two (or more) cases: Read and Write. This prevents race conditions, but only if the VI is non reentrant. However, implementation is still difficult.
Control References:
I also have read and heard about control references. I have had much use for them, for controlling the appearance of controls and indicators (and decoratiopns too, I guess...). However, I would caution you on using them to pass data around. This violates dataflow in a big way, as you are passing around pointers, instead of data. I believe this is difficult to implement, and even more difficult to keep straight. I personally recommend using them only for attributes of FP components, not for passing data.
So, what do I believe is the most elegant solution? I think a data server is your best bet. This is close to a LabVIEW 2 style global, but a little more active. Simply write all of your data into a subVI in any manner, a queue, a FIFO, LIFO, etc. Then, retrieve the data as desired. Buffering, queuing, etc are all handled by the data storage and retrieval subVI. It becomes sort of a small active database. The two sides (storage and retrieval) are independent of each other, and the code is all handled in the function. A basic version is a LIFO, Last In First Out, wherein the data is overwritten constantly. The data is then read by the reading VI, the front panel VI in your case, at any time, and the data is always the latest. You can add complexity as you need, such as making it a FIFO. This is done by simply writing the data to an array, then reading back the oldest value (by reversing the array and reading index 0.)
I believe this is an elegant solution to your problem. It does maintain dataflow, except that time is taken out of the equation, depending on how you look at it. It simplifies your program because you only need to do three things. Write the data handler, then drop in the function into the VI that writes, and the one that reads. It is also flexible in handling the data.
Good luck, and let us all know how you do.

What's the difference between global variables and instance variables?

hi im just a biginner,
but what is the difference between these two?
both i declare them above the constructor right.
and both can access by any method in the class but my teacher said
global variables are not permitted in java....
but i don't know what that means....and i got started to confuse these two types,,
im confusing.......
and why my teacher said declaring global variables is not permitted,,,,,,
why.....

instance variables are kindof like Global variables. I'm not surprised you are confused.
The difference is not in how they are declared, but rather in how they are used.
There are two different "styles" of programming
- procedural programming.
- object oriented programming.
Global variables are a term from Procedural programming.
In this style of programming, you have only one class, and one "main" procedure. You only create one instance of the class, and then "run" it.
There is one thread of control, which goes through various methods/procedures to accomplish your task.
In this style of programming instance variables ARE "global" variables. They are accessible to all methods. There is only one instance of the class, and thus only one instance of the variables.
Global variables are "bad" BECAUSE you can change them in any method you like. Even from places that shouldn't have to. Also if you use the same name as a global variable and a local variable, you can cause great trouble. This can lead to very subtle bugs, as the procedures interact in ways you don't expect.
The preferred method in procedural programming is to pass the values as parameters to the methods, and only refer to the parameters, and local variables. This means that you can track exactly what your method is doing, and what it affects. It makes it simpler to understand. If you use global variables in your methods, it becomes harder to understand.
So when are instance variables not global variables?
When you are actually using the class as an Object, rather than just a program to run. If you are creating multiple instances of an object, all with different values for their instance variables, then they are not global variables. For instance you declare a Person object with an attribute "firstname". Your "main" program then creates many instances of the Person object, each with their own "firstname"
I guess at the end of all this, it comes down to definitions.
Certainly you can write procedural code in java. You can treat your instance variables, for all intents and purposes like global variables.
I can only think to show a sort of example
public class Test1
   User[] users;
   public void printUsers(){
     // loop through and print all the users
     // uses a global variable
      for(int i=0; i<users.length; i++){
        users.printUser();
public void printUsers(User[] users){
// preferred method - pass it the info it needs to do the job
for(int i=0; i<users.length; i++){
users[i].printUser();
public Test1(){
User u1 = new User("Tom", 20);
User u2 = new User("Dick", 42);
User u3 = new User("Harry", 69);
users = new User[3];
users[0] = u1;
users[1] = u2;
users[2] = u3;
printUsers();
printUsers(users);
public static void main(String[] args)
new Test1();
class User{
String firstName;
int age;
public User(String name, int age){
this.firstName = name;
this.age = age;
public void printUser(){
// here they are used as instance variables and not global variables
System.out.println(firstName + " Age: " + age);
Shit thats a lot of typing, and I'm not even sure I've explained it any good.
Hope you can make some sense out of this drivel.
Cheers,
evnafets

Use of global variables like g_cnt_transactions_transferred in the LSMW

Hi SapAll.
when i had a look at the some of the LSMW's whic use IDOC as the object of uploading data into SAP from external Files i have found in the coding under the step "Maintain Field Mapping and Conversion Rules" that they use some of the global variables like below
.if p_trfcpt = yes or sy-saprl >= '46A'.
EDI_DC40-DOCNUM = g_cnt_transactions_transferred + 1.
endif.
.EDI_DC40-CIMTYP = g_cimtyp.
.EDI_DC40-MESTYP = g_mestyp.
.EDI_DC40-MESCOD = g_mescod.
.if p_filept = yes.
EDI_DC40-SNDPOR = g_fileport.
elseif p_trfcpt = yes.
EDI_DC40-SNDPOR = g_trfcport.
endif.
my doubt is where i can find these variables 'g_cnt_transactions_transferred ','g_cimtyp','g_mescod','g_fileport','g_trfcport' in the LSMW and what is the use of the variable 'g_cnt_transactions_transferred ' in the LSMW.
I have treid to find out the above listed variables looking in step 'Maintain Field Mapping and Conversion Rules' under global variabels list and the other lists also but i couldnt found.
can any one help me in this ?
regards.
Seetha.

Hi Seetha,
In the LSMW Workbench go to the option user menu. And check the option display conversion program.
Now when you execute with the radio button on dislplay conversion program, you ll see the code that got generated in the background while you built your LSMW.
The global variables that you have mentioned are bound to be there in this program generated in the background..
You can put a break point here and see for yourself what the value of these global variables are at runtime.
File port, TRFC port , no. of transactions executed by one run of the LMSW Idoc program , message type are some of the fields that you have asked for .
Regards,
Arun

Java Threads vs. Native Global Variables

A brief description of the problem:
I am trying to integrate a multi-threaded Java app with legacy Fortran code. The Fortran code in question makes extensive use of global variables in the form of Fortran's Common Block data structure.
If multiple threads were allowed access to a native routine, they would over write each others data which is stored in global variables.
If only one thread at a time can have access to the native routine for the duration of the native routine, the whole advantage of using threads is completely nullified.
These native routines cannot be rewritten (3rd party code) and must be used.
One solution I envisioned was to load a new copy of the native shared object code for each Java object that used the native code. However, it seems System.loadLibrary() can only be used in a static context.
Is there any known solution to this problem?

Here is an elaboration on the earlier suggestions. It's a high overhead solution, because you have to start a bunch of JVMs.
1. You have a java control program, which will start up a pool of "services", make requests to them, and gather the results.
2. Each service is a small java program with a native method:
o java communications front-end.
o native method declaration.
o native - in your case fortran - method implementation.
3. Each service is started using "exec". That puts it in a separate process.
4, Since each service is a java program, you can use java to do communications between the control program and the service.
o You could use RMI.
o You could - perhaps - use java Process communications, i.e., have the services write to stdout, and have the control program capture the output.
o You could use socket communications.

Unit Testing and APEX Global Variables

We've recently started to unit test our database level PL/SQL business logic.
As such we have a need to be able to simulate or provide output from PL/SQL APEX components in order to facilitate testing of these components.
Some of the most obvious portions that need simulation are:
1. The existence of a session
2. The current application ID
3. The current page ID.
We currently handle requirement #1 by using apex_040100.wwv_flow_session.create_new
We handle 2 and 3 using the apex_application.g_flow_id and g_flow_step_id global variables.
I'm just wondering, how safe is it for us to use wwv_flow_session.create_new to simulate the creation of a session at testing time for those things which need a session?
I've also noticed that there are apex_application.get_application_id and apex_application.get_page_id functions whose output is not tied to the global variables (at least in our current version).
Is it safe for us to expect that we can set these global variables for use in testing or is apex moving to get_application_id and get_page_id functions away from global variables?
Will there be corresponding set_application_id and set_page_id functions in the future?
Sorry for the question bomb. Thanks for any help.

My first question would be why do you need to establish a session to test your PL/SQL?
wwv_flow_session is a package internal to APEX, and you should probably leave it be.
The get_application_id procedure you refer to is in apex_application_install, which is used for scripting installation of applications - not get/set of page ID like you're describing.
If you're uncomfortable using apex_application.g_flow_id, you can use v('APP_ID') or preferably pass the app_id/page_id as parameters to your procedures.
Your question seems to have a few unknowns, so that's the best I can describe.
Scott

Can F4IF_INT_TABLE_VALUE_REQUEST FM return a value in a global variable?

Hi everybody,
I need to use F4IF_INT_TABLE_VALUE_REQUEST FM because I have to let users select an specific option before choosing another value. The point is that I need to save in a program global variable what the user selects, and decide something with it in the program.
Is it possible that F4IF_INT_TABLE_VALUE_REQUEST FM returns the value in a sinple variable or it has to be paramter?
I look in a lot of previous threads but I didn't find anything, and I don't know if it's possible.
Thanks and kind regards,
MMP.

Hi,
Sure you can. All you need to do is to store what the function returns in your global variable. It don't need to be returned back to screen field.
DATA: BEGIN OF VALUES OCCURS 0,
         CARRID TYPE SPFLI-CARRID,
         CONNID TYPE SPFLI-CONNID,
       END OF VALUES.
DATA: VALUES_TAB TYPE TABLE OF VALUES,
          G_VALUE TYPE SPFLI-CONNID. "global variable to store what is returned
"in PAI first populate your table
SELECT CARRID CONNID
    FROM SPFLI
    INTO CORRESPONDING FIELDS OF TABLE VALUES_TAB
    UP TO 10 ROWS.
"then call the function but don't return the value to screen field
"If you specify the import parameters DYNPPROG, DYNPNR, and DYNPROFIELD, the useru2019s selection is
"returned to the corresponding field on the screen. If you specify the table parameter RETURN_TAB, the
"selection is returned into the table instead.
CALL FUNCTION 'F4IF_INT_TABLE_VALUE_REQUEST'
       EXPORTING
            RETFIELD         = 'CONNID'
            VALUE_ORG        = 'S'
       TABLES
            VALUE_TAB        = VALUES_TAB
            RETURN_TAB      = RETURN_TAB.
"now simply read first row of return tab and store the value returned there in some global var
READ RETURN_TAB INDEX 1.
MOVE RETURN_TAB-FIELDVAL TO G_VALUE.
Regards
Marcin

Problem with .DLL and global variables

Hi,
I need some helps to figure out my problem.
I wrote a .dll file to open and run a GUI. When I run it at the first time, it is ok. When I call it again, there is an error "Pointer to free memory passed to library. It will be ok if I completely exit the program that calls the .dll before re-call it. I think there is some problems with global variables when I call another thread. How can I free global variables between threads. Is there any solution for this problem?
Thanks

Vinh Pham:
Are you doing anything intentionally that frees your globals?
CVI ships with an example program that demonstrates calling a DLL to create a user interface: guidll.cws.
I made two simple modifications to guidll.cws.
1. In guidll.c, I made hpanel global by moving its declaration from RunDLLUI() to right below the #include statements.
2. In useguidll.c, I duplicated the lines calling RunDLLUI () and MessagePopup() to call the DLL gui twice.
I built the project and ran it. I had no problems with free'ed globals.
Take a look at the guidll example.
Can you either post your code or a modification to guidll that demonstrates the problem you're having?

Control global variable used in sub vi

Hi,
I've created a vi to read an instrument and to initiate its calibration with labview. This VI stores data in a global variable containing measurments and status of the instrument.
Now what I'm trying to do is create a sub vi with this to read&write 2 exactly identical instruments so I can finally create a VI that read all 3 instruments simultaneously.
How could I create a control on the global variable used by the sub VIs since it is the only thing that will change along with its COM port ?
I included a screetshot of the current VI.
Thanks,
Attachments:
Read_Calibrate.PNG ‏61 KB

I would make an array of values and then you just pass in which value to update. I would actually take it a step further and make an Action Engine that can update the data and return the data.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Loading a text file into a global variable issue - really a global var?

From all the documentation and examples I can find, it appears that it would be
correct to create a global array variable [outside of any functions] to load image names into,
then use these images for a slideshow. I want to make the app dynamic, in that changing the text file gives a new set of images.
The global variable goes null [no values] after the load event listener. Why is that?
Isn't global, well global, and alive for the duration of the SWF?
PARAMS.TXT:
monthNames=January,February,March,April,May,June,July,August,September,October,November,De cember&dayNames=Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday
CODE:
var dNames:Array = new Array();
var mNames:Array = new Array();
var request:URLRequest = new URLRequest("images/params.txt");
var variables:URLLoader = new URLLoader();
variables.dataFormat = URLLoaderDataFormat.VARIABLES;
variables.addEventListener(Event.COMPLETE, completeHandler);
try
variables.load(request);
catch (error:Error)
trace("Unable to load URL: " + error);
trace("2 mNames 2: " + mNames[2]);
trace("2 dNames 3: " + dNames[3]);
stop();
function completeHandler(event:Event):void
var loader:URLLoader = URLLoader(event.target);
dNames = loader.data.dayNames.split(",");
mNames = loader.data.monthNames.split(",");
trace(loader.data.dayNames);
trace("1 mNames 2: " + mNames[2]);
trace("1 dNames 3: " + dNames[3]);
OUTPUT:
2 mNames 2: undefined
2 dNames 3: undefined
Sunday,Monday,Tuesday,Wednesday,Thursday,Friday,Saturday
1 mNames 2: March
1 dNames 3: Wednesday
How do I access these values after loading from the external file, after the load?
Thanks in advance.

The statement you quoted from whatever Adobe documentation is correct.
If you want to load the data into the arrays before anything else happens, then have anything else that happens execute via the completeHandler function... after the data is loaded and processed into the arrays.
the command: loadFile() executes before the trace("2:" +images[4]); command. The loadFile function is processed and the loading process BEGINS... but starting the loading does not delay the main processing from continuing down the line--the loading itself becomes a secondary/background task. The command was to execute the loadFile function and the processing of that function was completed. If you don't believe so, then add a trace...
function loadFile():void
     vars.dataFormat = URLLoaderDataFormat.VARIABLES;
     vars.addEventListener(Event.COMPLETE, onComplete, false, 0, true);
     vars.load(new URLRequest("images/fnames.txt"));
     trace("started loading");
If you add that trace, you should see that the loadFile function execution is completed and the next line in your code is then processed... trace(2....)
The addEventlistener does not stop anything. The addEventListener code is assigning a monitor, not a traffic controller... it is telling the monitor to indicate when the data has finished loading. It is not telling anything to stop program execution.
So if you want to wait until the data is loaded before you do anything else... it goes....
function onComplete(evt:Event):void
     var urlVars:URLVariables = evt.target.data;
     images = vars.data.images.split(",");
     tnails = vars.data.thumbnails.split(",");
     ................HERE.................

How do i create and pass a global variable from one vi to several sub-vi's?

Hi Guys,
I am trying to create a program that opens several front panels (sub-VI's) in sequence. in each front panel, the user would open a file that the name is obtained from the previous sub-VI. I would like to know how i could pass the filename and refnum of the file thorough from one sub-vi to another. A global variable would do it in VB, but how do we do global vars in LABWIEW. thanks
Papish

I put together a sample VI and Sub VI that illustrates how to pass a Refnum and access a data file while in a Sub VI.
For multiple VIs just repeat the sub VI process.
You probably don't wanna use a Global Variable if not needed (can add to the mess down the road haha).
Let me know if it helps you out! Or if I can clarify anything else!
Chances are if you have seen VI in the forest it hasn't fallen.
Attachments:
Passing Refnum.zip ‏21 KB

Serious Global Variable Bug in Crosstabs

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