diff --git a/Sources/BindingGenerator/CLI.swift b/Sources/BindingGenerator/CLI.swift
index 916a65c..ad650de 100644
--- a/Sources/BindingGenerator/CLI.swift
+++ b/Sources/BindingGenerator/CLI.swift
@@ -13,7 +13,11 @@ nonisolated(unsafe) let _stderr = stderr
 
 struct StandardError: TextOutputStream {
   mutating func write(_ string: String) {
-    for byte in string.utf8 { putc(numericCast(byte), _stderr) }
+    let utf8 = string.utf8                                                                                       
+    utf8.withContiguousStorageIfAvailable { _ = fwrite($0.baseAddress, 1, $0.count, _stderr) } ?? { 
+        var buf = Array(utf8);
+        fwrite(&buf, 1, buf.count, _stderr) 
+    }() 
   }
 }
 nonisolated(unsafe) var standardError: StandardError = StandardError()