(Win32 API) Code snippets

Page overview

How to: Obtain all window handles?
How to: obtain a window's text?
How to: get the last error?
Topic links

How to: Obtain all window handles?

Example to get a std::map of std::string and HWND.

include <map>

include <string>

include <windows>


std::map<std::string,HWND> getWindows(const HWND& anyHandle)
{
  std::map<std::string,HWND> myWindows;
  const int sizeBuffer = 100;
  char buffer[sizeBuffer];
  HWND handle = GetWindow(anyHandle,GW_HWNDFIRST);
  while(handle!=0)
  {
    GetWindowText(handle,buffer,sizeBuffer);
    if (std::string(buffer)!="") myWindows[std::string(buffer)] = handle;
    handle = GetNextWindow(handle,GW_HWNDNEXT);
  }
  return myWindows;
}

Note that window handles move in memory in time! So you cannot retrieve them once at the start of your program (thus making the std::map const).

How to: obtain a window's text?

Easier function around GetWindowText.

std::string getWindowText(const HWND& handle)
{
  const int sizeBuffer = 100;
  char buffer[sizeBuffer];
  GetWindowText(handle,buffer,sizeBuffer);
  const std::string windowText(buffer);
  return windowText;
}

How to: get the last error?

Easier function for around GetLastError

std::string getLastError()
{
  LPVOID lpMsgBuf;
  FormatMessage(
      FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM,
      0,
      GetLastError(),
      MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
      (LPTSTR) &lpMsgBuf,
      0,
      0
  );
  //Transform to std::string
  const std::string lastError = (char*)lpMsgBuf; //A dirty cast!
  // Free the buffer.
  LocalFree( lpMsgBuf );
  //Return the std::string
  return lastError;
}

Topic links

last edited (May 20, 2007) by bilderbikkel, Number of views: 1683, Current Rev: 1

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