// If gettid() could not be used, we use one of the following.
#if defined OS_LINUX
return getpid(); // Linux: getpid returns thread ID when gettid is absent
-#elif defined OS_WINDOWS || defined OS_CYGWIN
+#elif defined OS_WINDOWS && !defined OS_CYGWIN
return GetCurrentThreadId();
#else
// If none of the techniques above worked, we use pthread_self().