diff --git a/lib/pointer.js b/lib/pointer.js
index <HASH>..<HASH> 100644
--- a/lib/pointer.js
+++ b/lib/pointer.js
@@ -53,7 +53,7 @@ Pointer.methodCallSuffixForType = function(typeDef) {
             // no hard mapping, so try to use size
             var sz      = FFI.sizeOf(typeDef),
                 szMap   = FFI.SIZE_TO_POINTER_METHOD_MAP[sz],
-                signed  = (typeDef != "byte" || typeDef.substr(0, 1) == "u");
+                signed  = (typeDef != "byte" && typeDef != "size_t" && typeDef.substr(0, 1) != "u");
             
             if (sz) {
                 // XXX: This is kind of a shitty way to detect unsigned/signed
Fix the determination for whether a non-specific type is signed