diff --git a/glm/gtx/ulp.hpp b/glm/gtx/ulp.hpp
index 18ce2f53..fce68d73 100644
--- a/glm/gtx/ulp.hpp
+++ b/glm/gtx/ulp.hpp
@@ -32,7 +32,7 @@ namespace glm
 		//! Return the number of ULP between 2 variables.
 		//! From GLM_GTX_ulp extension.
 		template <typename genType>
-		genIType ulp(
+        std::size_t ulp(
 			genType const & a,
 			genType const & b);