diff --git a/src/USB2.cpp b/src/USB2.cpp
index c029ee0d3b2b508bc64b9657b18a491b9a5d6f44..b9d74b16192e2ac9544200ba64b0504397b896e3 100644
--- a/src/USB2.cpp
+++ b/src/USB2.cpp
@@ -525,7 +525,7 @@ void USB2::write(const Tango::DevVarCharArray *argin)
 		goto error;
 	
 	while (bytes_total < bytes_to_write) {
-		ssize_t bytes_written;
+		int bytes_written;
 		conn_state = libusb_bulk_transfer(dev_handle, ep_down, 
 				argin_data.data() + bytes_total,
 				bytes_to_write - bytes_total, &bytes_written, timeout);