diff --git a/app/QCPDialog.h b/app/QCPDialog.h
index 84dd59d..13a3fb0 100644
--- a/app/QCPDialog.h
+++ b/app/QCPDialog.h
@@ -1,8 +1,11 @@
 #ifndef QCPDIALOG_H
 #define QCPDIALOG_H
 
-#include <QAbstractPrintDialog>
+extern "C" {
 #include <CPDFrontend.h>
+}
+
+#include <QAbstractPrintDialog>
 
 class QPrinter;
 class QGridLayout;