All Questions
26
questions
1
vote
1
answer
214
views
JNA: Callback returns null value
I am using custom types in the callback method and always get an empty value. What could be the problem?
C code in dll(i have .h file for this dll):
typedef union
{
char caStruct[16384];
struct
...
- 13
2
votes
1
answer
547
views
Pointer to a function in java
I have a dynamic link library (DLL) written in c++. In my DLL I have a function like this:
void set_event_callback(EVENT_CALLBACK callback_fcn);
where EVENT_CALLBACK is a function pointer like this:
...
- 63
0
votes
0
answers
87
views
JNA callback method wont be called until futureTask.get() timeout
If I run like this, the callback block will not run so future.get() will block forever:
FutureTask<Long> futureTask = new FutureTask<>(System::currentTimeMillis);
boolean login = ...
- 1
2
votes
0
answers
72
views
Is the WindowProcedure always called in the JavaFX Application Thread?
In a JavaFX app, if I use the JNA to implement a custom window procedure, will the callback always be on the JavaFX Application Thread?
public class MyWindowProc implements WinUser.WindowProc
...
...
- 317
0
votes
1
answer
71
views
Is is possible to specify a JNA callback programmatically?
I know how to specify a JNA callback (C to Java) the regular way, like for example:
C header:
static void (*InvokerInst)(int, int);
__declspec(dllexport) int start();
__declspec(dllexport) void ...
- 523
0
votes
1
answer
309
views
Copy data from an unmanaged memory pointer to a managed unsigned byte array in Java
I have a c# code I am trying to implement in Java using JNA currently stuck in returning a preview image during my device scan process
C#
[DllImport("RS_SDK.dll",
CharSet = CharSet....
- 570
1
vote
1
answer
207
views
How can I delay return of CallNextHookEx or PostMessage to simulate delayed mouse events?
My mouse does occasional double clicks and now I'm trying to build a tool that detects invalid mouseup/mousdowns and blocks them from being propagated.
The double-clicks are actually triggered by the ...
- 814
1
vote
1
answer
153
views
JAVA-JNA : I can't modify a structure field throughout a callback function
I have a problem with JNA callbacks. In my JAVA program I use a function pointer that will be called by a native library. This function pointer is:
public int callback(S_CODELINE_INFO codelineInfo)
{
...
1
vote
1
answer
114
views
Jvm crash when second call to the callback happens
I using JNA to call native library
My callback interface
public interface PPAEvent extends Callback{
void callback(int eventCode, int opCode, String Data);
}
I have a callback implementation ...
- 33
1
vote
0
answers
231
views
JNA - callback method with typedef struct** argument
I am using C dll with this code:
1)
AIC_BRIDGE_API AIC_ERROR_CODE aic2_set_cb_function (
void (*cb2_start_dsts) (AIC2_DSTS_START_STOP),
void (*cb2_stop_dsts) (AIC2_DSTS_START_STOP),
...
- 11
0
votes
1
answer
45
views
why am I not getting any output when a method with a callback is called?
I am trying to call a method which is in a C DLL through Java. But I am not getting any output nor any exceptions. Below is my C code.
typedef void (*rfid_data)(
uint32_t data_id,
uint32_t ...
- 4,137
2
votes
2
answers
2k
views
JNA callback function with pointer to structure argument
I am busy with a project in which I have to do native calls to a proprietary C library. I came across JNA, which seems to be tried and tested with a number of successful projects.
I am having trouble ...
- 313
1
vote
1
answer
3k
views
Using JNA, how do I create a 'C++ class' and pass it to a C++ function,?
I need to call a proprietary DLL function with the following prototype (simplified for clarity):
int J_Image_OpenStream(J_IMG_CALLBACK_OBJECT obj, J_IMG_CALLBACK_FUNCTION function);
The type ...
- 9,451
0
votes
1
answer
516
views
Pass a raw function pointer where the JNA definition expects a Callback?
I'm working with a JNA interface that expects a Callback. I have the raw address of a native function g, which is the function I want to install as a callback. I am calling native function f, which ...
- 4,705
2
votes
1
answer
2k
views
C++ binary to Java gets "java.lang.Error: Invalid memory access"
I have a Java library interfacing (via JNA) with a native C++ DLL. This DLL provides functions to set callbacks that are invoked when certain hardware events occur.
All of these callbacks work except ...
- 82