diff --git a/src/libCom/osi/os/posix/osdThread.h b/src/libCom/osi/os/posix/osdThread.h
index 576995aef..d8c3a54e2 100644
--- a/src/libCom/osi/os/posix/osdThread.h
+++ b/src/libCom/osi/os/posix/osdThread.h
@@ -12,6 +12,6 @@
 
 #include <pthread.h>
 
-pthread_t epicsThreadGetPosixThreadIdSelf ( epicsThreadPrivateId id );
+pthread_t epicsThreadGetPosixThreadIdSelf ( epicsThreadId id );
 
 #endif /* osdThreadh */