Execute command using Win32 - c++

Question

I would like to execute shell command to update firmware to my procesor ATMega 2560 like this:
avrdude.exe -c breakout -P ft0 -p m2560 -U flash:w:\"file.cpp.hex\":a
I can do it by ShellExecute() function:
ShellExecute(0, L"open", L"cmd.exe", L"/C avrdude.exe -c breakout -P ft0 -p m2560 -U flash:w:\"file.cpp.hex\":a > log.txt", 0, SW_HIDE);
But I want to redirect output buffer, so I think I should use CreateProcess() function. I tried this but it hasn't worked.
CreateProcess(NULL, L"cmd /C avrdude.exe -c breakout -P ft0 -p m2560 -U flash:w:\"file.cpp.hex\":a", NULL, NULL, 0, 0, NULL, NULL, NULL, NULL);

Answer 1

Use CreateProcess() instead of ShellExecute(), and provide your own pipes so you can read the process's output. MSDN has an article on that topic:
Creating a Child Process with Redirected Input and Output
For example:
LPWSTR cmdLine[] = L"avrdude.exe -c breakout -P ft0 -p m2560 -U flash:w:\"file.cpp.hex\":a";
SECURITY_ATTRIBUTES sa = {0};
sa.nLength = sizeof(sa);
sa.lpSecurityDescriptor = NULL;
sa.bInheritHandle = TRUE;
HANDLE hStdOutRd, hStdOutWr;
HANDLE hStdErrRd, hStdErrWr;
if (!CreatePipe(&hStdOutRd, &hStdOutWr, &sa, 0))
{
// error handling...
}
if (!CreatePipe(&hStdErrRd, &hStdErrWr, &sa, 0))
{
// error handling...
}
SetHandleInformation(hStdOutRd, HANDLE_FLAG_INHERIT, 0);
SetHandleInformation(hStdErrRd, HANDLE_FLAG_INHERIT, 0);
STARTUPINFO si = {0};
si.cbSize = sizeof(si);
si.dwFlags = STARTF_USESTDHANDLES;
si.hStdInput = GetStdHandle(STD_INPUT_HANDLE);
si.hStdOutput = hStdOutWr;
si.hStdError = hStdErrWr;
PROCESS_INFORMATION pi = {0};
if (!CreateProcessW(NULL, cmdLine, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi))
{
// error handling...
}
else
{
// read from hStdOutRd and hStdErrRd as needed until the process is terminated...
CloseHandle(pi.hThread);
CloseHandle(pi.hProcess);
}
CloseHandle(hStdOutRd);
CloseHandle(hStdOutWr);
CloseHandle(hStdErrRd);
CloseHandle(hStdErrWr);

Answer 2

Problem was resolved!
Full code:
STARTUPINFO si = { sizeof(STARTUPINFO) };
PROCESS_INFORMATION pi;
if (!CreateProcess(L"C:\\Windows\\System32\\cmd.exe",
L" /C avrdude.exe -c breakout -P ft0 -p m2560 -U flash:w:\"file.cpp.hex\":a",
NULL, NULL, 0, 0, NULL, NULL, &si, &pi))
{
printf("CreateProcess failed (%d).\n", GetLastError());
return -1;
}