C++ executable opens a command window - c++

I have this very simple C++ class which just opens a blank Windows window, but I've noticed that everytime I double click the .exe, it opens the window, but it also opens a command prompt window too.
Is there a quick easy & simple way to stop this command prompt window from happening?
Cheers in advance,
KS.
#include <windows.h>
const char g_szClassName[] = "myWindowClass";
// Step 4: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_LBUTTONDOWN:
{
char szFileName[MAX_PATH];
HINSTANCE hInstance = GetModuleHandle(NULL);
GetModuleFileName(hInstance, szFileName, MAX_PATH);
MessageBox(hwnd, szFileName, "This program is:", MB_OK | MB_ICONINFORMATION);
}
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 1;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Step 2: Creating the Window
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"WinApp-2",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// Step 3: The Message Loop
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}

Just link with the /SUBSYSTEM:WINDOWS option instead of /SUBSYSTEM:CONSOLE.
If you're currently letting the compiler call the linker, you may want to pass /c to cl.exe to compile only, and then call link.exe /SUBSYSTEM:WINDOWS on the resulting object file(s).

Related

SetWindowRgn changes window theme to Classic

When i use the SetWindowRgn function in my windows api code, the created windows style changes from Modern to Classic.
Minumum code to reproduce problem here:
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hwnd = CreateWindowEx(
WS_EX_TOPMOST | WS_EX_CLIENTEDGE,
g_szClassName,
"Capture Screen",
WS_OVERLAPPEDWINDOW,
10, 100, 800, 600,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, SW_NORMAL);
UpdateWindow(hwnd);
HRGN WindowRgn = CreateRectRgn(0,0,800,600);
SetWindowRgn(hwnd,WindowRgn,TRUE); // <===== comment, uncomment this line to observe difference
MSG Msg;
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
Commenting and uncommenting the line below will demonstrate the problem
SetWindowRgn(hwnd,WindowRgn,TRUE); // <===== comment, uncomment this line to observe difference
Modern (commenting the line) :
Classic (uncommenting the line) :
Any idea what exactly in the function causes the problem here? And any fixes for this?

Visual Studio Watch Window show WClass whenever I debug a simple windows application from its execuatble

Here's the code for just displaying a window using WinApi
For ref this code is from here.
#include <windows.h>
const char g_szClassName[] = "myWindowClass";
// Step 4: the Window Procedure
LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch(msg)
{
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG Msg;
//Step 1: Registering the Window Class
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.lpszMenuName = NULL;
wc.lpszClassName = g_szClassName;
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
if(!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
// Step 2: Creating the Window
hwnd = CreateWindowEx(
WS_EX_CLIENTEDGE,
g_szClassName,
"The title of my window",
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT, CW_USEDEFAULT, 240, 120,
NULL, NULL, hInstance, NULL);
if(hwnd == NULL)
{
MessageBox(NULL, "Window Creation Failed!", "Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
// Step 3: The Message Loop
while(GetMessage(&Msg, NULL, 0, 0) > 0)
{
TranslateMessage(&Msg);
DispatchMessage(&Msg);
}
return Msg.wParam;
}
Then I open the executable in Visual Studio 2019 with:
cl -Zi example.cpp user32.lib
devenv example.exe
When I run it using F5, I get this in the Watch Window:
NAME = WClass
VALUE = Unable to evaluate the expression. Operation not supported. Unknown error: 0x80070057.
On hovering over the VALUE I get this: The value for this item is stale due to a problem that occurred while evaluating it.
On hovering over the refresh button I get this: The value of this expression may be incorrect. It could not be evaluated because: "
This problem however does not arise when I open a Windows Application Project in Visual Studio and dump this code. In that case, when I build the solution, the Watch Window is empty.
PS: The Program runs properly as expected but I am curious why WClass shows up in Watch Window.
The watch window doesn't do anything on its own. The user has to enter a symbol or expression for it to become active.
If your watch window shows an entry with name WClass, then that's an entry you entered. Given the code you provided, there is no symbol with that name, so the debugger cannot evaluate it.
If this is freaking you out, just delete the entry in your watch window. When done, switch to the Autos and Locals window. That's probably what you were looking for anyway.

winapi doesn't respond to keypress

I recently decided to learn a bit of WinApi, but I hit a snag. I want to display a massage in my window after a keypress, but it doesn't seem to work. If I press the key multiple times or if I hold it down, still nothing happens. Can you tell me what I'm doing wrong?
This is the full code:
#include <windows.h>
#include <string.h>
#include <stdlib.h>
#include <tchar.h>
LRESULT CALLBACK WndProc (HWND hwnd,
UINT uMsg,
WPARAM wParam,
LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
LPCWSTR display_str = L"hello";
switch(uMsg)
{
case WM_PAINT:
hdc = BeginPaint(hwnd, &ps);
if(GetAsyncKeyState(VK_UP))
{
TextOut(hdc,
15, 15,
display_str,
_tcslen(display_str));
}
EndPaint(hwnd, &ps);
break;
case WM_CLOSE:
DestroyWindow(hwnd);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, uMsg, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
HWND hwnd;
MSG uMsg;
HINSTANCE hInst;
WNDCLASSEX wcex;
LPCWSTR class_name = L"myWindowClass";
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc = WndProc;
wcex.cbClsExtra = 0;
wcex.cbWndExtra = 0;
wcex.hInstance = hInstance;
wcex.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
wcex.hCursor = LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName = NULL;
wcex.lpszClassName = class_name;
wcex.hIconSm = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_APPLICATION));
if(!RegisterClassEx(&wcex))
{
MessageBox(NULL, L"Call to RegisterClassEx failed!", L"Win32 Guided Tour!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hInst = hInstance;
hwnd = CreateWindowEx(
NULL,
class_name,
L"Test",
WS_OVERLAPPEDWINDOW,
200, 200,
740, 540,
NULL,
NULL,
hInstance,
NULL
);
if(!hwnd)
{
MessageBox(NULL, L"Window Creation Failed!", L"Error!",
MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
while(GetMessage(&uMsg, NULL, 0, 0) > 0)
{
TranslateMessage(&uMsg);
DispatchMessage(&uMsg);
}
return uMsg.wParam;
}
Windows sends WM_KEYDOWN message when a key is pressed. In WndProc handle WM_KEYDOWN message, call InvalidateRect with the Client rect of the window and draw the text you want to display in WM_PAINT message handler.
Here's my example, if pressed F11 key, print in console string.:
case WM_KEYDOWN:
if(wParam==VK_F11)
{
std::cout << "Hello in my example!";
}
break;

Creating a window doesn't work but gives no error messages

I'm trying to create a window, none appear but I don't get an error message anywhere except for the one I put in testing hWnd.
#define WIN32_LEAN_AND_MEAN
#include <Windows.h>
#include "entity.h"
LRESULT CALLBACK WndProc (HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
switch(message)
{
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, message,wParam,lParam);
}
return 0;
}
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wcex;
wcex.cbSize = sizeof(WNDCLASSEX);
wcex.style = CS_HREDRAW | CS_VREDRAW;
wcex.lpfnWndProc= (WNDPROC)WndProc;
wcex.cbClsExtra= 0;
wcex.cbWndExtra= 0;
wcex.hInstance= hInstance;
wcex.hIcon= 0;
wcex.hCursor= LoadCursor(NULL, IDC_ARROW);
wcex.hbrBackground= (HBRUSH)(COLOR_WINDOW+1);
wcex.lpszMenuName= 0;
wcex.lpszClassName= "Extt";
wcex.hIconSm= 0;
if(!RegisterClassEx(&wcex))
{
MessageBox(NULL, "FAILED TO REGISTER WINDOW CLASS", "ERROR", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
HWND hWnd = CreateWindow("WinD", "Chair", WS_OVERLAPPEDWINDOW, 480, 480, 480, 480, NULL, NULL, hInstance, NULL);
if (hWnd == NULL)
{
MessageBox(NULL, "FAILED TO CREATE WINDOW", "ERROR", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
MSG msg;
while (GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return (int)msg.wParam;
}
I just don't know what to do anymore.
I did everything like the guy said, I've read and re-read the page several times and can not understand why this won't work.
Your classname parameters do not match. If you had used GetLastError() it would have returned 1407, which is:
ERROR_CANNOT_FIND_WND_CLASS
1407 (0x57F)
Cannot find window class.
Either change wcex.lpszClassName = "Extt"; to wcex.lpszClassName = "WinD"; or change the first parameter to CreateWindow to "Extt".

How to duplicate a window's clientarea to another window?

I want to create a simple project (the language doesn't really matter/but I prefer C++) which simply takes a window title as it's input and duplicate it's visual part, bit by bit, to a new window. just like a mirror better I'd say.
As far as I remember there was a win32 API for this but I can't remember, so would you please tell me how can I achieve this?
And please tell me, will your answers work with DirectX/Open-GL applications as well or not?
You can get DC of first window, and get DC of second window. And after this do BitBlt or StretchBlt. It has to work... But I don't know what about DirectX/Open-Gl... I think it has to work too. But anyway. It won't take much time to check it.
Here is the source code for a program that will mirror other apps, you can use StretchBlt() instead of BitBlt(), this will not copy Menubars or popups.
Some apps like chrome, calculator, and camera use child windows for the visual part, and FindWindow() only scans through top-level windows for the title, so you can use FindWindowEx() with it to make that work!
#include <windows.h>
HWND sourceWindow;
void Mirror(HWND hwndSource, HWND hwndDst)
{
HDC source = GetDC(hwndSource);
HDC dst = GetDC(hwndDst);
RECT srcSiz;
GetClientRect(hwndSource, &srcSiz);
SetWindowPos(hwndDst, NULL, 0, 0, srcSiz.right, srcSiz.bottom, SWP_NOMOVE | SWP_NOZORDER);
BitBlt(dst, 0, 0, srcSiz.right, srcSiz.bottom, source, 0, 0, SRCCOPY);
ReleaseDC(hwndSource, source);
ReleaseDC(hwndDst, dst);
}
LRESULT CALLBACK WndProc(HWND hwnd, UINT Message, WPARAM wParam, LPARAM lParam)
{
switch (Message)
{
case WM_CREATE:
SetTimer(hwnd, 1, 500, (TIMERPROC) NULL);//This will refresh after every 500 ms
break;
case WM_TIMER:
Mirror(sourceWindow, hwnd);
break;
case WM_DESTROY:
KillTimer(hwnd, 1);
break;
default:
return DefWindowProc(hwnd, Message, wParam, lParam);
}
return 0;
}
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
HWND hwnd;
MSG msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(hInstance, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(CreateSolidBrush(RGB(0, 0, 0)));
wc.lpszMenuName = NULL;
wc.lpszClassName = "MyWindow";
wc.hIconSm = LoadIcon(hInstance, IDI_APPLICATION);
if (!RegisterClassEx(&wc))
{
MessageBox(NULL, "Window Registration Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
hwnd = CreateWindowEx(WS_EX_OVERLAPPEDWINDOW, "MyWindow", "MyTitle", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 500, 500,
NULL, NULL, hInstance, NULL);
if (!hwnd)
{
MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK);
return 0;
}
ShowWindow(hwnd, nCmdShow);
UpdateWindow(hwnd);
sourceWindow = FindWindowA(NULL, "<WindowTitle>");//or you can use class name
while(GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}