diff --git a/portable/ThirdParty/GCC/Posix/port.c b/portable/ThirdParty/GCC/Posix/port.c
index 66095fb2c..5dc7f45f8 100644
--- a/portable/ThirdParty/GCC/Posix/port.c
+++ b/portable/ThirdParty/GCC/Posix/port.c
@@ -303,8 +303,8 @@ BaseType_t xPortStartScheduler( void )
         memset( ( void * ) &hSigSetupThread.__opaque, 0, sizeof( hSigSetupThread.__opaque ) );
         memset( ( void * ) &hThreadKeyOnce.__opaque, 0, sizeof( hThreadKeyOnce.__opaque ) );
     #else /* Linux PTHREAD library*/
-        hSigSetupThread = PTHREAD_ONCE_INIT;
-        hThreadKeyOnce = PTHREAD_ONCE_INIT;
+        hSigSetupThread = ( pthread_once_t ) PTHREAD_ONCE_INIT;
+        hThreadKeyOnce = ( pthread_once_t ) PTHREAD_ONCE_INIT;
     #endif /* __APPLE__*/
 
     /* Restore original signal mask. */