C++ launching program without console opening

Question

I have been working on an application to set the desktop background basing of another application I found here: http://www.optimumx.com/downloads.html#SetWallpaper. The idea is to set the background to a wallpaper every 10 minutes, so it launches the SetWallpaper.exe with the command 'SetWallpaper.exe /D:S Wallpaper.jpg' but when I launch my application it creates a console window that doesn't automatically close and when I manually close it, it kills the exe.

#include <windows.h>
int main() {
int i = 1;
int j = 3;
// refresh = time until refresh in minutes
int refresh = 10;
// 1000 milliseconds = 1 second
int second = 1000;
int minute = 60;
int time = second * minute * refresh;
while (i < j) {
system("cmd /c start /b SetWallpaper.exe /D:S Wallpaper.jpg");
Sleep(time);
}
return 0;
}

I tried using 'sleep.exe' that comes with MinGW Msys but that creates a new process each team, eventually hogging all the processes.

Thanks in advance!

Answer 1

The first problem you're having is that you've created your program as a console application with a main method. Instead, create it as a Win32 Project with a WinMain entry point. This will be invoked directly without creating a console window.

EDIT: The second issue is addressed by Ferruccio's answer in that you're invoking another console application from yours which will also result in a console window being created.

Answer 2

You're going about it the hard way. It's fairly simple to change the Windows wallpaper in a program:

#include <windows.h>

SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, (PVOID) "path/to/wallpaper.jpg", SPIF_UPDATEINIFILE);

In any case, if you insist on launching an external program to do it. Use CreateProcess. It has the ability to launch console mode apps without a visible window, by setting the dwCreationFlags parameter to CREATE_NO_WINDOW.

Answer 3

Set ShowWindow to false and don't forget to FreeConsole at the end.

#include <windows.h>


int main(void)
{

   ShowWindow(FindWindowA("ConsoleWindowClass", NULL), false);

   // put your code here

   system("cmd /c start /b SetWallpaper.exe /D:S Wallpaper.jpg");

   FreeConsole();

   return 0;
}

And as Ferruccio mentioned, You can use SetTimer and SystemParametersInfo to trigger a change periodically.

#define STRICT 1 
#include <windows.h>
#include <iostream.h>

VOID CALLBACK TimerProc(HWND hWnd, UINT nMsg, UINT nIDEvent, DWORD dwTime) 
{

  LPWSTR wallpaper_file = L"C:\\Wallpapers\\wallpaper.png";
  int return_value = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, wallpaper_file, SPIF_UPDATEINIFILE);


  cout << "Programmatically change the desktop wallpaper periodically: " << dwTime << '\n';
  cout.flush();
}

int main(int argc, char *argv[], char *envp[]) 
{
    int Counter=0;
    MSG Msg;

    UINT TimerId = SetTimer(NULL, 0, 2000, &TimerProc); //2000 milliseconds = change every 2 seconds

    cout << "TimerId: " << TimerId << '\n';
   if (!TimerId)
    return 16;

   while (GetMessage(&Msg, NULL, 0, 0)) 
   {
        ++Counter;
        if (Msg.message == WM_TIMER)
        cout << "Counter: " << Counter << "; timer message\n";
        else
        cout << "Counter: " << Counter << "; message: " << Msg.message << '\n';
        DispatchMessage(&Msg);
    }

   KillTimer(NULL, TimerId);
return 0;
}