windows: add SetStdHandle

https://msdn.microsoft.com/en-us/library/windows/desktop/ms686244(v=vs.85).aspx

Change-Id: If7d460a9fb43767c0a3ee55e86faf3356162c81d
Reviewed-on: https://go-review.googlesource.com/39609Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

windows/syscall_windows.go

@@ -94,6 +94,7 @@ func NewCallbackCDecl(fn interface{}) uintptr
 //sys	SetFilePointer(handle Handle, lowoffset int32, highoffsetptr *int32, whence uint32) (newlowoffset uint32, err error) [failretval==0xffffffff]
 //sys	CloseHandle(handle Handle) (err error)
 //sys	GetStdHandle(stdhandle uint32) (handle Handle, err error) [failretval==InvalidHandle]
+//sys	SetStdHandle(stdhandle uint32, handle Handle) (err error)
 //sys	findFirstFile1(name *uint16, data *win32finddata1) (handle Handle, err error) [failretval==InvalidHandle] = FindFirstFileW
 //sys	findNextFile1(handle Handle, data *win32finddata1) (err error) = FindNextFileW
 //sys	FindClose(handle Handle) (err error)

windows/zsyscall_windows.go

@@ -78,6 +78,7 @@ var (
 	procSetFilePointer                     = modkernel32.NewProc("SetFilePointer")
 	procCloseHandle                        = modkernel32.NewProc("CloseHandle")
 	procGetStdHandle                       = modkernel32.NewProc("GetStdHandle")
+	procSetStdHandle                       = modkernel32.NewProc("SetStdHandle")
 	procFindFirstFileW                     = modkernel32.NewProc("FindFirstFileW")
 	procFindNextFileW                      = modkernel32.NewProc("FindNextFileW")
 	procFindClose                          = modkernel32.NewProc("FindClose")
@@ -633,6 +634,18 @@ func GetStdHandle(stdhandle uint32) (handle Handle, err error) {
 	return
 }
 
+func SetStdHandle(stdhandle uint32, handle Handle) (err error) {
+	r1, _, e1 := syscall.Syscall(procSetStdHandle.Addr(), 2, uintptr(stdhandle), uintptr(handle), 0)
+	if r1 == 0 {
+		if e1 != 0 {
+			err = errnoErr(e1)
+		} else {
+			err = syscall.EINVAL
+		}
+	}
+	return
+}
+
 func findFirstFile1(name *uint16, data *win32finddata1) (handle Handle, err error) {
 	r0, _, e1 := syscall.Syscall(procFindFirstFileW.Addr(), 2, uintptr(unsafe.Pointer(name)), uintptr(unsafe.Pointer(data)), 0)
 	handle = Handle(r0)