diff --git a/src/libCom/osi/os/posix/osdThread.h b/src/libCom/osi/os/posix/osdThread.h
index 0d3009504..c89a6be48 100644
--- a/src/libCom/osi/os/posix/osdThread.h
+++ b/src/libCom/osi/os/posix/osdThread.h
@@ -12,6 +12,14 @@
 
 #include <pthread.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 pthread_t epicsThreadGetPosixThreadId ( epicsThreadId id );
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* osdThreadh */