// The steps for redirecting child process's STDOUT:
// 1. Save current STDOUT, to be restored later.
// 2. Create anonymous pipe to be STDOUT for child process.
// 3. Set STDOUT of the parent process to be write handle to
// the pipe, so it is inherited by the child process.
// 4. Create a noninheritable duplicate of the read handle and
// close the inheritable read handle.
// Save the handle to the current STDOUT.
hSaveStdout = GetStdHandle(STD_OUTPUT_HANDLE);
// Create a pipe for the child process's STDOUT.
if (! CreatePipe(&hChildStdoutRd, &hChildStdoutWr, &saAttr, 0))
ErrorExit("Stdout pipe creation failed\n");
// Set a write handle to the pipe to be STDOUT.
if (! SetStdHandle(STD_OUTPUT_HANDLE, hChildStdoutWr))
ErrorExit("Redirecting STDOUT failed");
// Create noninheritable read handle and close the inheritable read
// handle.
// The steps for redirecting child process's STDIN:
// 1. Save current STDIN, to be restored later.
// 2. Create anonymous pipe to be STDIN for child process.
// 3. Set STDIN of the parent to be the read handle to the
// pipe, so it is inherited by the child process.
// 4. Create a noninheritable duplicate of the write handle,
// and close the inheritable write handle.
// Save the handle to the current STDIN.
hSaveStdin = GetStdHandle(STD_INPUT_HANDLE);
// Create a pipe for the child process's STDIN.
if (! CreatePipe(&hChildStdinRd, &hChildStdinWr, &saAttr, 0))
ErrorExit("Stdin pipe creation failed\n");
// Set a read handle to the pipe to be STDIN.
if (! SetStdHandle(STD_INPUT_HANDLE, hChildStdinRd))
ErrorExit("Redirecting Stdin failed");
// Duplicate the write handle to the pipe so it is not inherited.
fSuccess = DuplicateHandle(GetCurrentProcess(), hChildStdinWr,
GetCurrentProcess(), &hChildStdinWrDup, 0,
FALSE, // not inherited
DUPLICATE_SAME_ACCESS);
if (! fSuccess)
ErrorExit("DuplicateHandle failed");
CloseHandle(hChildStdinWr);
// Now create the child process.
if (! CreateChildProcess())
ErrorExit("Create process failed");
// After process creation, restore the saved STDIN and STDOUT.
if (! SetStdHandle(STD_INPUT_HANDLE, hSaveStdin))
ErrorExit("Re-redirecting Stdin failed\n");
if (! SetStdHandle(STD_OUTPUT_HANDLE, hSaveStdout))
ErrorExit("Re-redirecting Stdout failed\n");