diff --git a/src/libsync/filesystem.h b/src/libsync/filesystem.h
index 9e314a191..07cbf17e9 100644
--- a/src/libsync/filesystem.h
+++ b/src/libsync/filesystem.h
@@ -124,10 +124,10 @@ bool openAndSeekFileSharedRead(QFile* file, QString* error, qint64 seek);
 QString fileSystemForPath(const QString & path);
 #endif
 
-QByteArray calcMd5( const QString& fileName );
-QByteArray calcSha1( const QString& fileName );
+QByteArray OWNCLOUDSYNC_EXPORT calcMd5( const QString& fileName );
+QByteArray OWNCLOUDSYNC_EXPORT calcSha1( const QString& fileName );
 #ifdef ZLIB_FOUND
-QByteArray calcAdler32( const QString& fileName );
+QByteArray OWNCLOUDSYNC_EXPORT calcAdler32( const QString& fileName );
 #endif
 
 }}
diff --git a/src/libsync/transmissionchecksumvalidator.h b/src/libsync/transmissionchecksumvalidator.h
index 24a289d7e..628e0a8d9 100644
--- a/src/libsync/transmissionchecksumvalidator.h
+++ b/src/libsync/transmissionchecksumvalidator.h
@@ -14,13 +14,15 @@
 
 #pragma once
 
+#include "owncloudlib.h"
+
 #include <QObject>
 #include <QByteArray>
 #include <QFutureWatcher>
 
 namespace OCC {
 
-class TransmissionChecksumValidator : public QObject
+class OWNCLOUDSYNC_EXPORT TransmissionChecksumValidator : public QObject
 {
     Q_OBJECT
 public: