diff --git a/fortran/src/H5Eff.F90 b/fortran/src/H5Eff.F90
index ca05a336fac..162a7508085 100644
--- a/fortran/src/H5Eff.F90
+++ b/fortran/src/H5Eff.F90
@@ -627,7 +627,7 @@ END FUNCTION H5Eget_msg
        RETURN
     ENDIF
     f_ptr = C_LOC(c_msg(1)(1:1))
-    c_msg_size = H5Eget_msg(msg_id, c_msg_type, f_ptr, msg_cp_sz+1)
+    c_msg_size = H5Eget_msg(msg_id, c_msg_type, f_ptr, msg_cp_sz+1_SIZE_T)
 
     CALL HD5c2fstring(msg, c_msg, msg_cp_sz, msg_cp_sz+1_SIZE_T)