C++ - How can I exit a program that has no window? - c++

Question

I'm new to C++, and I made myself a little program that can launch program through typing a command on the keyboard. In order to be able to launch a program whenever I want, I decided to set up a Low Level Keyboard Hook, which keep tracking key strokes and launch the specific program when the specific command was detected. The simple windows program was used to install the hook, the windows is not showed because all I need is the hook to listen in the background.
So far it works fine, however, the minor but annoying problem is I have to terminate the program through Windows Task Manager, and it's quite inconvenient. I have managed to uninstall the hook by pressing F7 key, but it seems that the windows program which is not showed is the Parent of the hook, so the hook cannot exit the windows program. While I want them both terminated through pressing a key. Hopefully I have made myself clear.
Is there any way that I could send a message from the hook to the windows program to ask it to exit? Or somehow I can terminate both of them in the hook program?
Thanks in advance.
Here is the code of the window program:
#include <windows.h>
#include "shortcut.h"
#pragma comment( lib, "libhook.dll.a") // Link Hook.lib to the project
long WINAPI WndProc(HWND hWnd, UINT wMessage, WPARAM wParam, LPARAM lParam)
{
switch(wMessage)
{
case WM_DESTROY:
InstallHook(FALSE); // Unhook
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, wMessage, wParam, lParam);
}
return 0;
}
BOOL FileExists(LPCTSTR szPath)
{
DWORD dwAttrib = GetFileAttributes(szPath);
return (dwAttrib != INVALID_FILE_ATTRIBUTES &&
!(dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
}
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
{
MSG msg;
WNDCLASS wndclass;
HANDLE hMutex = NULL;
char szAppName[20] = "shortcut";
hMutex = CreateMutex(NULL,TRUE,szAppName); //启动多线程
int dwRet = GetLastError();
if (hMutex)
{
if (dwRet == ERROR_ALREADY_EXISTS)
{
MessageBox(NULL, "Program is already runing.", "Oops!", MB_OK | MB_ICONINFORMATION);
CloseHandle(hMutex);
return FALSE;
}
}
wndclass.style=0;
wndclass.lpfnWndProc=(WNDPROC)WndProc;
wndclass.cbClsExtra=0;
wndclass.cbWndExtra=0;
wndclass.hInstance=hInstance;
wndclass.hIcon=NULL;
wndclass.hCursor=LoadCursor(NULL, IDC_ARROW);
wndclass.hbrBackground=(HBRUSH)GetStockObject(GRAY_BRUSH);
wndclass.lpszMenuName=NULL;
wndclass.lpszClassName=(LPSTR)szAppName;
if(!RegisterClass(&wndclass))
return FALSE;
if (!FileExists("\\ShortCuts.txt"))
{
MessageBox(NULL, "Missing file: cannot load shortcut settings file.(Shortcuts.txt)", "ERROR",MB_OK|MB_ICONINFORMATION);
exit(1);
}
if (!InstallHook(TRUE))
exit(1);
while(GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}
Here is the code of the hook program:
// Hook- a project to create the DLL and LIB files.
// Microsoft Visual C++ 6.0 and above steps:
// 1. Create a new Win32 Dynamic Link - Library project.
// 2. Add hook.cpp and hook.h to the project.
// 3. There is no step 3 :-). Just build your project and you will find
// a Hook.dll and Hook.lib file in your map.
#include <windows.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <ctime>
#include <map>
#include <process.h>
using namespace std;
HHOOK hHook;
HINSTANCE ghDLLInst=0;
const char startChar = ';';
bool bChecking = false;
string cmd;
typedef map<string,string> COMMANDMAP;
COMMANDMAP mShortcut;
string logfilename="log.txt";
ofstream LOG;
__declspec(dllexport)int InstallHook(BOOL bCode);
BOOL APIENTRY DllMain(HANDLE hModule, DWORD dwFunction, LPVOID lpNot)
{
ghDLLInst=(HINSTANCE)hModule;
return TRUE;
}
DWORD WINAPI Runsystem(LPVOID lpParam)
{
WinExec((LPCSTR)lpParam, SW_SHOW);
}
string gettime()
{
time_t curTime;
struct tm *locTime;
char buf[80];
time(&curTime);
locTime=localtime(&curTime);
strftime(buf,80,"%Y-%m-%d %H:%M:%S",locTime);
string s=buf;
return s;
}
ostream& tout()
{
return LOG<< gettime()<< ": ";
}
void StartCheck()
{
bChecking=true;
cmd.clear();
}
void EndCheck()
{
bChecking=false;
cmd.clear();
}
LRESULT CALLBACK KeyboardProc(int nCode, WPARAM wParam, LPARAM lParam)
{
if ((wParam == WM_KEYDOWN) && (nCode >= HC_ACTION)) // Only record when key pressed
{
KBDLLHOOKSTRUCT *pStruct = (KBDLLHOOKSTRUCT*)lParam;
switch (pStruct->vkCode)
{
case VK_RETURN:
{
if (bChecking)
{
COMMANDMAP::iterator it;
it=mShortcut.find(cmd);
if (it!=mShortcut.end())
{
tout()<<"received command \'"<<cmd<<"\', executing \'"<<it->second.c_str()<<endl;
CreateThread(NULL, 0, Runsystem, (void*)it->second.c_str(),0,NULL);
}
else {
tout()<<"received command \'" <<cmd<<"\', no matching."<<endl;
}
}
EndCheck();
break;
}
case VK_F7:
{
InstallHook(false);
break;
}
default: // Normal keys, convert them
{
BYTE KeyboardState[256];
GetKeyboardState(KeyboardState);
WORD CharValue;
if(ToAscii(pStruct->vkCode, pStruct->scanCode,KeyboardState,&CharValue,0) > 0) // Convert to char.
{
char character=char(CharValue);
// tout()<<"received keyCode: "<<pStruct->vkCode<< " char: "<< character<<endl;
if (bChecking)
{
cmd+=character;
}
if (!bChecking && (character == startChar))
{
// tout()<<"Start checking..."<<endl;
StartCheck();
}
}
break;
}
}
}
return (int)CallNextHookEx(hHook, nCode, wParam, lParam);
}
bool readline(ifstream &fin,string &sline)
{
do
{
getline(fin,sline);
} while (!fin.eof() && ((sline[0]=='/' && sline[1]=='/') || sline.empty()));
return fin.eof()?false:true;
}
// __declspec(dllexport) means that this function must be exported to a dll file.
__declspec(dllexport)int InstallHook(BOOL bCode)
{
if(bCode)
{
// initialize shortcuts
ifstream fin;
LOG.open(logfilename.c_str(),ios_base::app);
tout()<<"Reading config file."<<endl;
fin.open("ShortCuts.txt");
if (fin)
{
string scmd,spath;
char oneline[256];
while(readline(fin,scmd)&&readline(fin,spath))
{
mShortcut[scmd]=spath;
// LOG<<scmd<<','<<spath<<endl;
}
fin.close();
tout()<<"OK, "<<mShortcut.size()<<" shortcuts loaded."<<endl;
}
else
{
tout()<<"ERROR"<<endl;
LOG.close();
exit(0);
}
hHook=(HHOOK)SetWindowsHookEx(WH_KEYBOARD_LL, (HOOKPROC)KeyboardProc, // Start the keyboard hook.
(HINSTANCE)GetModuleHandle(NULL), NULL);
if(!hHook)
{
tout()<<"Install hook failed."<<endl;
return 0;
}
else
{
tout()<<"Install hook successful."<<endl;
return 1;
}
}
else
{
if (MessageBox(NULL,"Are you sure to exit KeyShortcut?","Exit",MB_YESNO|MB_ICONWARNING)==IDYES)
{
tout()<<"Uninstall hook successful."<<endl;
LOG.close();
return UnhookWindowsHookEx(hHook); // Unhook the keyboardhook.
}
}
}

Answer 1

For instance, you can use RegisterHotKey API function to set your own hotkey to a system and then handle this hotkey's message in your program(windowless)
Added:
If you want to send quit message from one process to another then your friend is PostThreadMessage(dwThreadId, WM_DESTROY, 0, 0);