diff --git a/src/util/StringBuffer.hxx b/src/util/StringBuffer.hxx
index a4dc4189a..07ce6dd31 100644
--- a/src/util/StringBuffer.hxx
+++ b/src/util/StringBuffer.hxx
@@ -35,14 +35,14 @@
 /**
  * A statically allocated string buffer.
  */
-template<typename T, size_t CAPACITY>
+template<typename T, std::size_t CAPACITY>
 class BasicStringBuffer {
 public:
 	typedef T value_type;
 	typedef T &reference;
 	typedef T *pointer;
 	typedef const T *const_pointer;
-	typedef size_t size_type;
+	typedef std::size_t size_type;
 
 	static constexpr value_type SENTINEL = '\0';
 
@@ -104,7 +104,7 @@ public:
 	}
 };
 
-template<size_t CAPACITY>
+template<std::size_t CAPACITY>
 class StringBuffer : public BasicStringBuffer<char, CAPACITY> {};
 
 #endif
diff --git a/src/util/StringFormat.hxx b/src/util/StringFormat.hxx
index 4fee2fc37..723591c69 100644
--- a/src/util/StringFormat.hxx
+++ b/src/util/StringFormat.hxx
@@ -36,13 +36,13 @@
 
 template<typename... Args>
 static inline void
-StringFormat(char *buffer, size_t size,
+StringFormat(char *buffer, std::size_t size,
 	     const char *fmt, Args&&... args) noexcept
 {
 	snprintf(buffer, size, fmt, args...);
 }
 
-template<size_t CAPACITY, typename... Args>
+template<std::size_t CAPACITY, typename... Args>
 static inline void
 StringFormat(StringBuffer<CAPACITY> &buffer,
 	     const char *fmt, Args&&... args) noexcept
@@ -50,7 +50,7 @@ StringFormat(StringBuffer<CAPACITY> &buffer,
 	StringFormat(buffer.data(), buffer.capacity(), fmt, args...);
 }
 
-template<size_t CAPACITY, typename... Args>
+template<std::size_t CAPACITY, typename... Args>
 static inline StringBuffer<CAPACITY>
 StringFormat(const char *fmt, Args&&... args) noexcept
 {