diff --git a/include/internal/catch_console_colour_impl.hpp b/include/internal/catch_console_colour_impl.hpp
index 0183f785..b20762f3 100644
--- a/include/internal/catch_console_colour_impl.hpp
+++ b/include/internal/catch_console_colour_impl.hpp
@@ -117,7 +117,7 @@ namespace {
     };
 
     inline bool shouldUseColourForPlatform() {
-        return isatty( fileno(stdout) );
+        return isatty(STDOUT_FILENO);
     }
 
     PosixColourImpl platformColourImpl;