diff --git a/src/libCom/osi/os/posix/epicsMath.h b/src/libCom/osi/os/posix/epicsMath.h
index 4ed0fdc51..7cd0bb409 100644
--- a/src/libCom/osi/os/posix/epicsMath.h
+++ b/src/libCom/osi/os/posix/epicsMath.h
@@ -19,7 +19,7 @@ extern "C" {
 
 #ifdef isfinite
 #  undef finite
-#  define finite(x) isfinite(x)
+#  define finite(x) isfinite((double)x)
 #endif
 
 epicsShareExtern float epicsNAN;