Pass on null handle values to child process

Author: ChrisDenton

library/std/src/sys/windows/process.rs

@@ -513,17 +513,15 @@ fn program_exists(path: &Path) -> Option<Vec<u16>> {
 impl Stdio {
     fn to_handle(&self, stdio_id: c::DWORD, pipe: &mut Option<AnonPipe>) -> io::Result<Handle> {
         match *self {
-            // If no stdio handle is available, then inherit means that it
-            // should still be unavailable so propagate the
-            // INVALID_HANDLE_VALUE.
             Stdio::Inherit => match stdio::get_handle(stdio_id) {
                 Ok(io) => unsafe {
                     let io = Handle::from_raw_handle(io);
                     let ret = io.duplicate(0, true, c::DUPLICATE_SAME_ACCESS);
                     io.into_raw_handle();
                     ret
                 },
-                Err(..) => unsafe { Ok(Handle::from_raw_handle(c::INVALID_HANDLE_VALUE)) },
+                // If no stdio handle is available, then propagate the null value.
+                Err(..) => unsafe { Ok(Handle::from_raw_handle(ptr::null_mut())) },
             },
 
             Stdio::MakePipe => {
@@ -730,9 +728,9 @@ fn zeroed_startupinfo() -> c::STARTUPINFO {
         wShowWindow: 0,
         cbReserved2: 0,
         lpReserved2: ptr::null_mut(),
-        hStdInput: c::INVALID_HANDLE_VALUE,
-        hStdOutput: c::INVALID_HANDLE_VALUE,
-        hStdError: c::INVALID_HANDLE_VALUE,
+        hStdInput: ptr::null_mut(),
+        hStdOutput: ptr::null_mut(),
+        hStdError: ptr::null_mut(),
     }
 }