diff --git a/log/log.c b/log/log.c
index fece9bc..f1fbaa5 100644
--- a/log/log.c
+++ b/log/log.c
@@ -103,7 +103,7 @@ int log_open(const char *filename)
     ret = log_open_file(file);
 
 	if(ret >= 0)
-        setvbuf(file, NULL, _IOLBF, 0);
+        setvbuf(file, NULL, IO_BUFFER_TYPE, 0);
 
     return ret;
 }
diff --git a/log/log.h b/log/log.h
index 03fdd62..5a53a87 100644
--- a/log/log.h
+++ b/log/log.h
@@ -9,6 +9,11 @@
 #define LOG_ENOTOPEN -4
 #define LOG_ENOTIMPL -5
 
+#ifdef _WIN32
+#define IO_BUFFER_TYPE _IONBF
+#else
+#define IO_BUFFER_TYPE _IOLBF
+#endif
 
 void log_initialize();
 int log_open_file(FILE *file);