How to set window text by its handle in another process? - c++

Question

For my purposes I need to set text for a window that belongs to another process using its HWND handle. I came up with the following code, but it doesn't seem to work:
BOOL SetWindowTextInAnotherProcess(HWND hWnd, LPCTSTR pStrText)
{
//Set text of the 'hWnd' (assuming that 'hWnd' is in another process)
//'pStrText' = ASCIIZ string to set
//RETURN:
// = TRUE if done
BOOL bRes = FALSE;
if(hWnd &&
pStrText)
{
DWORD dwProcID = 0;
::GetWindowThreadProcessId(hWnd, &dwProcID);
if(dwProcID)
{
HANDLE hProc = ::OpenProcess(PROCESS_VM_READ | PROCESS_VM_WRITE | PROCESS_VM_OPERATION, FALSE, dwProcID);
if(hProc)
{
int nLn = lstrlen(pStrText);
int ncbSzStr = (nLn + 1) * sizeof(TCHAR);
VOID* pVMem = ::VirtualAllocEx(hProc, NULL, ncbSzStr, MEM_COMMIT, PAGE_READWRITE);
if(pVMem)
{
SIZE_T sztWrtn = 0;
if(::WriteProcessMemory(hProc, pVMem, pStrText, ncbSzStr, &sztWrtn))
{
if(sztWrtn == ncbSzStr)
{
DWORD_PTR dwMsgRes = 0xCCCCABAB;
if(::SendMessageTimeout(hWnd, WM_SETTEXT, NULL, (LPARAM)pVMem,
SMTO_NORMAL | SMTO_ABORTIFHUNG | SMTO_ERRORONEXIT,
1000 * 2,
&dwMsgRes))
{
//Check result
if(dwMsgRes != 0xCCCCABAB &&
dwMsgRes == TRUE)
{
//Done
bRes = TRUE;
}
}
}
}
//Free mem
::VirtualFreeEx(hProc, pVMem, ncbSzStr, MEM_DECOMMIT);
}
::CloseHandle(hProc);
}
}
}
return bRes;
}
SendMessageTimeout returns FALSE and GetLastError returns 0.
Any idea what am I doing wrong?
PS. Both processes are running non-elevated on the same desktop.