diff --git a/common/alog.cpp b/common/alog.cpp
index 7d93a373..4d5a7aad 100644
--- a/common/alog.cpp
+++ b/common/alog.cpp
@@ -14,6 +14,9 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+#ifdef _WIN64
+#define _POSIX_C_SOURCE 1
+#endif
 #include "alog.h"
 #include "lockfree_queue.h"
 #include "photon/thread/thread.h"
@@ -251,7 +254,11 @@ class LogOutputFile final : public BaseLogOutput {
         if (log_file_fd < 0) return;
         uint64_t length = end - begin;
         iovec iov{(void*)begin, length};
+#ifndef _WIN64
         ::writev(log_file_fd, &iov, 1); // writev() is atomic, whereas write() is not
+#else
+        ::write(log_file_fd, iov.iov_base, iov.iov_len);
+#endif
         throttle_block();
         if (log_file_name && log_file_size_limit) {
             log_file_size += length;
diff --git a/thread/test/test.cpp b/thread/test/test.cpp
index afaf6164..36404a98 100644
--- a/thread/test/test.cpp
+++ b/thread/test/test.cpp
@@ -1465,8 +1465,14 @@ TEST(workpool, async_work_lambda_threadpool_append) {
     LOG_INFO("DONE");
 }
 
+#if defined(_WIN64)
 #define SAVE_REG(R) register uint64_t R asm(#R); volatile uint64_t saved_##R = R;
-#define CHECK_REG(R) asm volatile ("" : "=r"(saved_##R) : "0"(saved_##R)); if (saved_##R != R) puts("differs after context switch!" #R);
+#define CHECK_REG(R) asm volatile ("" : "=m"(saved_##R)); if (saved_##R != R) puts(#R " differs after context switch!");
+#else
+#define SAVE_REG(R)
+#define CHECK_REG(R)
+#endif
+
 void* waiter(void* arg) {
     auto p = (int*)arg;
     LOG_INFO("Start", VALUE(p), VALUE(*p));
diff --git a/thread/test/x.cpp b/thread/test/x.cpp
index 0c35e8d5..3bf8ba69 100644
--- a/thread/test/x.cpp
+++ b/thread/test/x.cpp
@@ -21,7 +21,7 @@ int DevNull(void* x, int)
 
 int (*pDevNull)(void*, int) = &DevNull;
 
-#ifdef TEST
+#ifdef ThreadUT
 
 #include "../thread.h"
 namespace photon {