diff --git a/include/libimp/def.h b/include/libimp/def.h
index a0ff342..25535bc 100644
--- a/include/libimp/def.h
+++ b/include/libimp/def.h
@@ -10,8 +10,8 @@
 #include <cstdint>
 
 #define LIBIMP_               imp
-#define LIBIMP_NAMESPACE_     LIBIMP_
-#define LIBIMP_NAMESPACE_BEG_ namespace LIBIMP_NAMESPACE_ {
+#define LIBIMP_NAMESPACE_     :: LIBIMP_
+#define LIBIMP_NAMESPACE_BEG_ namespace LIBIMP_ {
 #define LIBIMP_NAMESPACE_END_ }
 
 LIBIMP_NAMESPACE_BEG_
diff --git a/include/libimp/detect_plat.h b/include/libimp/detect_plat.h
index 687e0d9..df3ac37 100644
--- a/include/libimp/detect_plat.h
+++ b/include/libimp/detect_plat.h
@@ -24,6 +24,8 @@
 # define LIBIMP_OS_ANDROID
 #elif defined(__linux__) || defined(__linux)
 # define LIBIMP_OS_LINUX
+#elif defined(_POSIX_VERSION)
+# define LIBIMP_OS_POSIX
 #else
 # error "This OS is unsupported."
 #endif