diff --git a/src/net/SocketError.hxx b/src/net/SocketError.hxx
index 3e98f4de3..d6171e807 100644
--- a/src/net/SocketError.hxx
+++ b/src/net/SocketError.hxx
@@ -191,6 +191,14 @@ SocketErrorCategory() noexcept
 #endif
 }
 
+[[gnu::pure]]
+static inline bool
+IsSocketErrorReceiveWouldBlock(const std::system_error &e) noexcept
+{
+	return e.code().category() == SocketErrorCategory() &&
+		IsSocketErrorReceiveWouldBlock(e.code().value());
+}
+
 [[gnu::pure]]
 static inline auto
 MakeSocketError(socket_error_t code, const char *msg) noexcept