diff --git a/src/tcxparser.cpp b/src/tcxparser.cpp
index f15734fc..f8ae8422 100644
--- a/src/tcxparser.cpp
+++ b/src/tcxparser.cpp
@@ -1,9 +1,9 @@
 #include "tcxparser.h"
 
 
-void TCXParser::warning(const char *text)
+void TCXParser::warning(const char *text) const
 {
-	QFile *file = static_cast<QFile *>(_reader.device());
+	const QFile *file = static_cast<QFile *>(_reader.device());
 	fprintf(stderr, "%s:%lld: %s\n", qPrintable(file->fileName()),
 	  _reader.lineNumber(), text);
 }
diff --git a/src/tcxparser.h b/src/tcxparser.h
index b11cb2c9..fa8cbb56 100644
--- a/src/tcxparser.h
+++ b/src/tcxparser.h
@@ -31,7 +31,7 @@ private:
 	qreal number();
 	QDateTime time();
 
-	void warning(const char *text);
+	void warning(const char *text) const;
 
 	QXmlStreamReader _reader;
 };