diff --git a/windows/syscall_windows.go b/windows/syscall_windows.go
index d249919c..1c2e80a9 100644
--- a/windows/syscall_windows.go
+++ b/windows/syscall_windows.go
@@ -215,7 +215,7 @@ func NewCallbackCDecl(fn interface{}) uintptr {
 //sys	CreateProcess(appName *uint16, commandLine *uint16, procSecurity *SecurityAttributes, threadSecurity *SecurityAttributes, inheritHandles bool, creationFlags uint32, env *uint16, currentDir *uint16, startupInfo *StartupInfo, outProcInfo *ProcessInformation) (err error) = CreateProcessW
 //sys	OpenProcess(desiredAccess uint32, inheritHandle bool, processId uint32) (handle Handle, err error)
 //sys	ShellExecute(hwnd Handle, verb *uint16, file *uint16, args *uint16, cwd *uint16, showCmd int32) (err error) [failretval<=32] = shell32.ShellExecuteW
-//sys	GetWindowThreadProcessId(hwnd HWND, pid *uint32) (tid uint32) = user32.GetWindowThreadProcessId
+//sys	GetWindowThreadProcessId(hwnd HWND, pid *uint32) (tid uint32, err error) = user32.GetWindowThreadProcessId
 //sys	GetShellWindow() (shellWindow HWND) = user32.GetShellWindow
 //sys	MessageBox(hwnd HWND, text *uint16, caption *uint16, boxtype uint32) (ret int32, err error) [failretval==0] = user32.MessageBoxW
 //sys	ExitWindowsEx(flags uint32, reason uint32) (err error) = user32.ExitWindowsEx
diff --git a/windows/zsyscall_windows.go b/windows/zsyscall_windows.go
index cd5e8528..8a79ea15 100644
--- a/windows/zsyscall_windows.go
+++ b/windows/zsyscall_windows.go
@@ -2904,9 +2904,12 @@ func GetShellWindow() (shellWindow HWND) {
 	return
 }
 
-func GetWindowThreadProcessId(hwnd HWND, pid *uint32) (tid uint32) {
-	r0, _, _ := syscall.Syscall(procGetWindowThreadProcessId.Addr(), 2, uintptr(hwnd), uintptr(unsafe.Pointer(pid)), 0)
+func GetWindowThreadProcessId(hwnd HWND, pid *uint32) (tid uint32, err error) {
+	r0, _, e1 := syscall.Syscall(procGetWindowThreadProcessId.Addr(), 2, uintptr(hwnd), uintptr(unsafe.Pointer(pid)), 0)
 	tid = uint32(r0)
+	if tid == 0 {
+		err = errnoErr(e1)
+	}
 	return
 }