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egerving wrote: use the MessageBox function a lot to see what going on with code
Why are you not using a debugger?
egerving wrote: API functions that return various types
Example? Again, if you use the debugger you'll see the return values.
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As a backup to Michael's suggestion, you could use TRACE() (with MFC) or OutputDebugString() to see those values.
"Old age is like a bank account. You withdraw later in life what you have deposited along the way." - Unknown
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
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Hi all, Im having a bit of trouble compiling a simple program (just a messagebox) in visual c++ (the full version, not express). I'm guessing there must be something I need to do or setup to get it working. The same code compiles just fine in codeblocks and visual c++ express. I wanna use visual c++ for the resource editor. Anyone has any idea why this is?
Here's the full code. Thanks.
#include <windows.h>
INT WINAPI wWinMain(HINSTANCE hInst,
HINSTANCE hPrevInst,
LPWSTR lpCmdLine,
INT nShowCmd)
{
int nResult=MessageBox(NULL,
"An example of Cancel,Retry,Continue",
"Hello Message Box!",
MB_ICONERROR|MB_ABORTRETRYIGNORE);
switch(nResult)
{
case IDABORT:
break;
case IDRETRY:
break;
case IDIGNORE:
break;
}
return 0;
}
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Adassus wrote: Im having a bit of trouble compiling a simple program
And what did you say the the compiler error message was?
"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown
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wWinMain uses wide-characters so you need to use wide strings.
int nResult=MessageBox(NULL,L"An example of Cancel,Retry,Continue",L"Hello MessageBox!",MB_ICONERROR|MB_ABORTRETRYIGNORE);
Conversely you could also change the entry point to WinMain[^] and change the character set in the General section to 'Not Set'
Best Wishes,
-David Delaune
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without knowing the error :
Unicode vs. MBSC ?
This signature was proudly tested on animals.
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The error is:
1>c:\documents and settings\john\my documents\visual studio 2008\projects\test\test\main.cpp(18) : error C2440: '=' : cannot convert from 'const char [13]' to 'LPCWSTR'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>c:\documents and settings\john\my documents\visual studio 2008\projects\test\test\main.cpp(28) : error C2664: 'MessageBoxW' : cannot convert parameter 2 from 'const char [29]' to 'LPCWSTR'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>c:\documents and settings\john\my documents\visual studio 2008\projects\test\test\main.cpp(42) : error C2664: 'CreateWindowExW' : cannot convert parameter 2 from 'const char [13]' to 'LPCWSTR'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>c:\documents and settings\john\my documents\visual studio 2008\projects\test\test\main.cpp(51) : error C2664: 'MessageBoxW' : cannot convert parameter 2 from 'const char [23]' to 'LPCWSTR'
1> Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
1>Build log was saved at "file://c:\Documents and Settings\john\My Documents\Visual Studio 2008\Projects\test\test\Debug\BuildLog.htm"
1>test - 4 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
#include <windows.h>
LRESULT CALLBACK WinProc(HWND hWnd,UINT message,WPARAM wParam,LPARAM lParam);
int WINAPI WinMain(HINSTANCE hInst,HINSTANCE hPrevInst,LPSTR lpCmdLine,int nShowCmd)
{
WNDCLASSEX wClass;
ZeroMemory(&wClass,sizeof(WNDCLASSEX));
wClass.cbClsExtra=NULL;
wClass.cbSize=sizeof(WNDCLASSEX);
wClass.cbWndExtra=NULL;
wClass.hbrBackground=(HBRUSH)COLOR_WINDOW;
wClass.hCursor=LoadCursor(NULL,IDC_ARROW);
wClass.hIcon=NULL;
wClass.hIconSm=NULL;
wClass.hInstance=hInst;
wClass.lpfnWndProc=(WNDPROC)WinProc;
wClass.lpszClassName="Window Class";
wClass.lpszMenuName=NULL;
wClass.style=CS_HREDRAW|CS_VREDRAW;
if(!RegisterClassEx(&wClass))
{
int nResult=GetLastError();
MessageBox(NULL,
"Window class creation failed",
"Window Class Failed",
MB_ICONERROR);
}
HWND hWnd=CreateWindowEx(NULL,
"Window Class",
"Windows application",
WS_OVERLAPPEDWINDOW,
200,
200,
640,
480,
NULL,
NULL,
hInst,
NULL);
if(!hWnd)
{
int nResult=GetLastError();
MessageBox(NULL,
"Window creation failed",
"Window Creation Failed",
MB_ICONERROR);
}
ShowWindow(hWnd,nShowCmd);
MSG msg;
ZeroMemory(&msg,sizeof(MSG));
while(GetMessage(&msg,NULL,0,0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return 0;
}
LRESULT CALLBACK WinProc(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam)
{
switch(msg)
{
case WM_DESTROY:
{
PostQuitMessage(0);
return 0;
}
break;
}
return DefWindowProc(hWnd,msg,wParam,lParam);
}
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Same problem, same solution.
Your project is configured for Unicode strings and your string literals are ANSI. To avoid asking the same question again you should make an attempt to learn the difference between Unicode strings and ANSI strings. I recommend the following:
1.) Right click on your project in the solution explorer.
2.) Choose the properties from the popup menu.
3.) Choose 'General' from the left treeview.
4.) In the 'Project Defaults' section view that the 'Character set' is set to Unicode.
This means your project is using Unicode strings. More information below:
About ANSI & Unicode[^]
C++ String Literals[^]
Unicode Programming Summary [^]
Some solutions:
1.) You could change your Character set to 'Not Set' or 'MultiByte character set' and the code above will compile.
2.) You could add an L prefix to the string literals to denote they are wide strings.
3.) You could encapsulate the string using the _T macro so the project will compile in both ANSI and Unicode settings.
Best Wishes,
-David Delaune
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thx alot, i did work! I appreciate the answer!
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Hi,
I'm developing a driver for a usb device.
I have already a driver sample that allows me to get data from my device.
And the sample code to interact with the device is a console application.
I need to get that data into a C# program and now I don't know what to do.
I can think in some options like:
- Do this directly in the driver layer (which is a big puzzle)
- Wrap the code of the sample app in a C++ dll which I can then use in the C# side (don't know which kind of project that belongs to)
So, I was looking for some lights in order to see where I should focus my development efforts.
Any help would be appreciatted.
With my best regards,
Nuno
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I suggest you write a DLL that exposes the functionality of your device in the API.
This is the most common way and you'll be able to use the DLL from whatever programming language.
"It's supposed to be hard, otherwise anybody could do it!" - selfquote
"High speed never compensates for wrong direction!" - unknown
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Hi sinosoidal,
The DeviceIoControl Function[^] can be called directly from your C# application. There is no need to create a C++ DLL when you can pass information to and from a device driver with the C# language.
Take a look in your USB driver code and look for the IRP_MJ_DEVICE_CONTROL entry point. Should be something like:
DriverObject->MajorFunction[IRP_MJ_DEVICE_CONTROL] = SomeFunction
This defines the function which processes IOCTL codes. All you need to do is define a new IOCTL code. You simply pass a pointer in the DeviceIoControl lpOutBuffer parameter and the device driver can write data into the buffer at this address. Its extremely simple.
I would recommend spending a few hours playing with the sample project at:
WinDDK\6001.18002\src\general\ioctl\
This will give you an idea about how simple communication with a device driver is.
If the data arriving on the USB device needs to fire an event to notify your usermode application you can view the sample located at:
WinDDK\6001.18002\src\general\event
I highly recommend investing a few hours experimenting with these samples. The C# language is full featured and there is no reason to write a native DLL if the parent application is managed. You can communicate with the device driver directly from your C# application.
Best Wishes,
-David Delaune
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Hi,
Thanks for the replies. That was good news for me. I'm trying to explorer the direct connection to the USB device from C# using DeviceIOControl.
I found an example with code from an article here in codeproject.
The example, basicly interacts with an pci card, but i have seen another example of interaction, but this time with an usb device and they both start with CreateFile passing the device GUID.
However, i cant have a valid handle. I think i'm passing the right guid of the device, because i'm getting it from the driver it self.
hFileHandle = INVALID_HANDLE_VALUE;
hFileHandle = CreateFile("{00873fdf-61a8-11d1-aa5e-00c04fb1728b}",
GENERIC_READ |
GENERIC_WRITE,
0,
(IntPtr)0,
OPEN_EXISTING,
0,
NULL);
if (hFileHandle == INVALID_HANDLE_VALUE)
{
Console.WriteLine("Cannot open driver handle");
return;
}
Any tips?
Thanks,
Nuno
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Hi David,
I made it! However it was a little hard to get the device name. But I made it! 
I have to try your suggestion to get the device name more genericly.
In what regards to read from the device, I'm using readfile function which was what the test app was calling, because, otherwise, I didn't knew which IO_CTL codes to use in order to invoke the request!
I'm still ambienting myself to the windows programming model.
Your help crucial guys.
Thank you very much,
With my best regards,
Nuno
PS: you'll see me again here for sure! 
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Hello,
i am reading the BMP file.. first as you know i must read info header then file info.. and then goes the reversed RGB data... i have written a code in C to read the rgb data, reverse it in a way i want...and save every pixel color in the big array of structures... my code seems to work very good...i created some BMP images using the MS Pain, tested it with my program...and everything was fine..
BUT... when i tried to get some pictures from internet, covert those pictures to BMP format..and read with my program, i found that my program (to be exact the fread functions inside it) read a value of 0. it just doesnt work with other pics! but it works perfect with the pics created by the MS Paint!
later.... i tried to do this.. i copied some part of MS Paint pictures into another BMP files created by MS Paint! and that pictures didnt work with my pgoram either!! very strange!
so it seems to me..that when i paint something in Paint.. and try to process with my program, it reads it fine... but when i try to copy/paste different fragments of these pictures, or copy/paste fragments from another pictures, my program reads zero values!
any ideas why? whats wrong? can anyone who worked with BMP files give me a hint?
thanks alot!
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which fread returns 0 ?
have you tried to read past the end of the file, or did you simply fail to open the file ?
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no i read only the amount of data which is needed for the current dimension of the picture..and i did it successfully, BUT... i read all the ZERO values.. thats it.. no errors, no program crashes...nothing bad...just fread returned 0 values...
any ideas?
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TeslaShock wrote: and then goes the reversed RGB data
Depends on the format of the bitmap. There are at least half a dozen common BMP formats, all documented.
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well, i read more about formats...but it seems to me that i do everything right, and my pictures are 24bit so no color table should be used there. The only difference is some formats have two unused bytes or one...after the rgb data... BUT in that case...during a read i would get the corrupted data! but...i read many many thousands of rgb values and all are ZERO...
i mean its not a problem of shifting the values... it just reads zeros! but i use the same MS Paint editor! and i do the bitmap copy/paste operations with that editor only...and copy from other pics... so what could be the problem...strange... ? 
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Hi
I designed a dialog box using "DlgProc" to handle message.
CMyDialog::CMyDialog()
{
...
GetOFN().lpfnHook = DlgProc;
...
}
UINT CALLBACK DlgProc(HWND hDlg, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
switch (uMsg)
{
}
return 0;
}
BOOL CMyDialog::OnInitDialog()
{
}
But OnInitDialog() is never called, how can I fix it
Best regards,
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Who and why should call it?
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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I have a "CButton" which pointer should be available.
I plan to use GetDlgItem() to get it. But this function only functions correctly in "OnInitDialog".
Thanks,
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transoft wrote: I have a "CButton" which pointer should be available.
Why do you need to have the pointer available and where ? If it is in your dialog class, you could simply associate a class member with that button.
transoft wrote: I plan to use GetDlgItem() to get it. But this function only functions correctly in "OnInitDialog".
No, that's wrong. Why would that function only work inside the OnInitDialog function ? That doesn't make any sense.
I think you really need to read a good book about the MFC because it seems you are totally confused about a lot of things. We won't be able to help you unless you grasp the basic concepts firsts.
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"Why do you need to have the pointer available and where ? If it is in your dialog class, you could simply associate a class member with that button."
From what you said, you have something to learn and they are not IN a good MFC book.
"No, that's wrong. Why would that function only work inside the OnInitDialog function ? That doesn't make any sense."
From what you said, you have something to learn.
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