I am working on a system where I want to intercept Direct3D calls to create tiled displays. I am using an APITrace like interceptor to create a message stream and recreating the calls in a second program, much like the old Chromium project. The application side works fine but the program that processes the message stream does not. What I find is that when I call CreateSwapChain() the function returns S_OK but GetLastError() returns 'error = 0x00000594 : Cannot set nonlocal hook without a module handle.' I check the error state with GetLastError() just prior to calling CreateSwapChain() and there is no error. This error makes no sense to me. Can anyone shed any light on this?
I found the problem. The parameters for the CreateSwapChain function the pDesc structure includes an output window handle. Since the message stream is packed with the arguments for the message processing side the window handle has to be replaced with correct handle before the function is called be the processor side.
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How to get the name of the calling program from within an asynchronous remote function call (aRFC) ?
CALL FUNCTION 'BAPI_MATERIAL_SAVEREPLICA' STARTING NEW TASK lv_taskname
DESTINATION IN GROUP DEFAULT
The called BAPI triggers a user exit that I need to disable for this particular calling program. However, the local part of the stack is lost after the RFC and the name of the calling program on the local system is unknown.
The closest solution I could think of was disabling the user exit when the calling program is SAPMSSY1 (RFC calls), but that it not as accurate.
Maybe the parameter CALLER_PROGRAM of the function module RFC_GET_ATTRIBUTES. I'm not sure it works in all kinds of RFC calls.
What I am doing is writing a WPF application to work with our device. The application writes some commands to the device and reads command's response from it. I got pinvoke declarations from pinvoke.net website for CreateFile, WriteFile, ReadFile, etc.
I made a function doing following things, CreateFile(with flag FILE_FLAG_OVERLAPPED
) to open device, WriteFile to send command, ReadFile to read response, WaitForSingleObject and GetOverlappedResult to capture timeout exception if device doesn't respond, and CloseHandle to close device.
This function always worked fine if I called it in UI thread. But I wanted to call it in background thread to keep UI active. So I created a thread in Window_Loaded method(Work is my function's name).
t = new Thread(Work);
t.Start();
Then ReadFile, WaitForSingleObject and GetOverlappedResult group may met error, these three functions returned success and GetOverlappedResult could capture correct read length returned from device. But no actual data read from device filled in the byte array buffer passed to ReadFile function. The failure rate was about 50%.
If I waited thread t to finish, then it always worked fine again.
t = new Thread(Work);
t.Start();
t.join();
Of cause UI would also hang in this situation.
I searched this problem but no exact same question was found. I tried to set background thread's apartment state to STA or MTA explicitly, but it didn't work.
t = new Thread(Work);
t.SetApartmentState(ApartmentState.STA);
t.Start();
It really confuses me. Please help me if you have any idea. Thank you for your reading.
I couldn't find the root cause. But I bypassed it by rewriting read process in C++ function and calling my C++ function with pInvoke.
Second question on here...
Basically I am having a problem with a Stackoverflow exception that is thrown in my program, and I literally have no idea on how to locate the cause..
I have a program which has a plugin system, and it's a program that utilizes TCP in order to send and receive data; Server-> Client. I am making a remote console plugin, and the problem occurs when I do the command 'tree'; the filesystem entries listing command. For the first few seconds everything goes alright; the commands are being outputted (sent from Client to server). The receiving packets event isn't thread safe, so in the API I've provided an invocation function (to invoke methods on the UI thread). So therefore on output, it will do the following:
Public Sub ClientReadPacket(Sender As IClient, Pipename As String, Values As Object())
Select Case DirectCast(Values(1), ConsoleCommands)
Case ConsoleCommands.Output
ServerGUI.Send(Sub() ConsoleOutput.AppendText(Values(2) & Environment.NewLine))
End Select
End Sub
As you can see, the ServerGUI is an interface that I have provided for plugin development. And in the actual program - in the class that implements the GUI interface, I get a stackoverflow exception right here:
Private Sub ISend(del As System.Threading.SendOrPostCallback) Implements IGUI.Send
UIThread.Send(del, Nothing)
End Sub ' The break point is here; I assume that means that the exception ocurs in the line above.
The UIThread object is a synchronizationcontext of the main thread.
http://i.gyazo.com/870d9667f2272969b650cea836adca50.png
Update: So far I've narrowed it down to the following; it must be causing stackoverflow exception when calling SynchronizationContext.Send() too often, and the same happens when I rather use Invoke() in the plugin, it also gives a Stackoverflow exception.
I tried using asyncoperation, and this does not crash, but due to the fact that it's solely asynchronous is a problem, because my program becomes unresponsive when using Post(), because it continuously Posts (due to the fact that it will manage the next packet before the asyncoperation has posted.
Let's say that a request is sent to server via xhrPost and server finds that request needs more information to be processed (for example a variable is missing), so, a response is sent back to client informing that request may have not been completely processed and this message is shown in a dialog box.
I was doing it sending from server an HTTP 202 status code, which I believe is not correct, and treating it on load function, where this message was displayed on a dialog box. But if I respond with some HTTP error code (ex: 400) the error is displayed in console (Note: in this case the message is treated in error function), as well as in my dialog box.
What is the best and correct way to do it?
Note that it is called a load handler, not a success handler.
The load hander is for valid, well formatted responses. These can contain a verity of status codes generated by your server side app that indicates success, failure, or something in between.
The error is just that, the server blew up while trying to process the request and whatever you get back is probably not something your widget was written to expect. For this reason, I recommend using the same error handler across your whole app.
The dojo documentation states:
Sometimes xhrGet calls will fail. Often these are 404 errors or server errors such as 500. The error parameter is another callback function that is only invoked when an error occurs. This allows you to control what happens when an error occurs without having to put a lot of logic into your load function to check for error conditions. The first parameter passed to the error function is a JavaScript Error object indicating what the failure was. Dojo doc
I'm trying to upload a file from a server directory to the SAP CRM System (attachment to an Opportunity), therefore I am using the method create_with_file of the cl_crm_documents class.
To call this method I am using a RFC-Function created by myself.
If I test my RFC-Function within the Function Builder, everything works fine.
If I execute the RFC from a external System (in my case MS-Outlook) an error occurs: "Exception: RFC callback server not available".
I started the debugger and the program runs about half way through (So the connection works):
The create_with_file calls a couple of functions until the RFC_START_PROGRAM function is called. The error occurs exactly at this line.
Does anybody know why the error occurs only if I call the function remotely? How to solve this?
I don't have access to a CRM system, but this is what's probably happening: The class you use tries to perform some action on the front-end PC using the SAP GUI. For this, it performs an RFC call back or the SAP GUI. This works fine as long as you are using the function builder because there's a GUI connection available. Once you use some other means to invoke the function module, the GUI is no longer there and the program won't work. I'd suggest you check the code to see whether there is some parameter or customization that allows you to suppress the RFC call...