diff --git a/fx/cstr.c b/fx/cstr.c
index e6535c7..97b70ef 100644
--- a/fx/cstr.c
+++ b/fx/cstr.c
@@ -359,7 +359,7 @@ fx_status cstr_to_size(const char *in, size_t *out)
 		return FX_ERR_BAD_STATE;
 	}
 
-	if (v > SIZE_T_MAX) {
+	if (v > SIZE_MAX) {
 		return FX_ERR_BAD_STATE;
 	}