--- a/io/copy.h
+++ b/io/copy.h
@@ -155,7 +155,7 @@
         output.flush();
         const auto totalBytes = static_cast<std::streamoff>(count);
         while (count) {
-            const auto bytesCopied = ::sendfile64(output.fileDescriptor(), input.fileDescriptor(), nullptr, std::min(count, bufferSize));
+            const auto bytesCopied = ::sendfile64(output.fileDescriptor(), input.fileDescriptor(), nullptr, count < bufferSize ? count : bufferSize);
             if (bytesCopied < 0) {
                 throw std::ios_base::failure(argsToString("sendfile64() failed: ", std::strerror(errno)));
             }