use const

diff --git a/libs/ardour/disk_reader.cc b/libs/ardour/disk_reader.cc
index e59c17c3db9da4fec1a73e12e8fc2670de7ae15e..69eb2e43ae17baf3c6a6a2e4b83be32911c3342c 100644 (file)
--- a/libs/ardour/disk_reader.cc
+++ b/libs/ardour/disk_reader.cc
@@ -1432,7 +1432,7 @@ DiskReader::refill_midi ()
                return 0;
        }
 
-       size_t  write_space = _midi_buf->write_space();
+       const size_t  write_space = _midi_buf->write_space();
        const bool reversed    = _session.transport_speed() < 0.0f;
 
        DEBUG_TRACE (DEBUG::DiskIO, string_compose ("MIDI refill, write space = %1 file frame = %2\n", write_space, file_frame[DataType::MIDI]));