diff --git a/src/OpenMesh/Core/IO/IOManager.hh b/src/OpenMesh/Core/IO/IOManager.hh
index 97ca9535..dc6d1a81 100644
--- a/src/OpenMesh/Core/IO/IOManager.hh
+++ b/src/OpenMesh/Core/IO/IOManager.hh
@@ -97,7 +97,7 @@ namespace IO {
     \see \ref mesh_io
 */
 
-class _IOManager_
+class OPENMESHDLLEXPORT _IOManager_
 {
 private:
   
diff --git a/src/OpenMesh/Core/IO/reader/BaseReader.hh b/src/OpenMesh/Core/IO/reader/BaseReader.hh
index 2befefc2..35c76ac4 100644
--- a/src/OpenMesh/Core/IO/reader/BaseReader.hh
+++ b/src/OpenMesh/Core/IO/reader/BaseReader.hh
@@ -82,7 +82,7 @@ namespace IO {
    data structure by the means of a BaseImporter derivative.
    All reader modules must be derived from this class.
 */
-class BaseReader
+class OPENMESHDLLEXPORT BaseReader
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/reader/OBJReader.hh b/src/OpenMesh/Core/IO/reader/OBJReader.hh
index d67f7b48..0845395c 100644
--- a/src/OpenMesh/Core/IO/reader/OBJReader.hh
+++ b/src/OpenMesh/Core/IO/reader/OBJReader.hh
@@ -79,7 +79,7 @@ namespace IO {
 /**
     Implementation of the OBJ format reader.
 */
-class _OBJReader_ : public BaseReader
+class OPENMESHDLLEXPORT _OBJReader_ : public BaseReader
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/reader/OFFReader.hh b/src/OpenMesh/Core/IO/reader/OFFReader.hh
index b203b126..116825ec 100644
--- a/src/OpenMesh/Core/IO/reader/OFFReader.hh
+++ b/src/OpenMesh/Core/IO/reader/OFFReader.hh
@@ -111,7 +111,7 @@ class BaseImporter;
 
 */
 
-class _OFFReader_ : public BaseReader
+class OPENMESHDLLEXPORT _OFFReader_ : public BaseReader
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/reader/OMReader.hh b/src/OpenMesh/Core/IO/reader/OMReader.hh
index ee13c5f9..96fdf18b 100644
--- a/src/OpenMesh/Core/IO/reader/OMReader.hh
+++ b/src/OpenMesh/Core/IO/reader/OMReader.hh
@@ -80,7 +80,7 @@ namespace IO {
     Implementation of the OM format reader. This class is singleton'ed by 
     SingletonT to OMReader.
 */
-class _OMReader_ : public BaseReader
+class OPENMESHDLLEXPORT _OMReader_ : public BaseReader
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/reader/PLYReader.hh b/src/OpenMesh/Core/IO/reader/PLYReader.hh
index 560b7ab2..671d1a89 100644
--- a/src/OpenMesh/Core/IO/reader/PLYReader.hh
+++ b/src/OpenMesh/Core/IO/reader/PLYReader.hh
@@ -89,7 +89,7 @@ class BaseImporter;
 
 */
 
-class _PLYReader_ : public BaseReader
+class OPENMESHDLLEXPORT _PLYReader_ : public BaseReader
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/reader/STLReader.hh b/src/OpenMesh/Core/IO/reader/STLReader.hh
index e7fa4e16..2f8afca5 100644
--- a/src/OpenMesh/Core/IO/reader/STLReader.hh
+++ b/src/OpenMesh/Core/IO/reader/STLReader.hh
@@ -83,7 +83,7 @@ class BaseImporter;
     Implementation of the STL format reader. This class is singleton'ed by
     SingletonT to STLReader.
 */
-class _STLReader_ : public BaseReader
+class OPENMESHDLLEXPORT _STLReader_ : public BaseReader
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/writer/BaseWriter.hh b/src/OpenMesh/Core/IO/writer/BaseWriter.hh
index 5f0a1429..16ce1937 100644
--- a/src/OpenMesh/Core/IO/writer/BaseWriter.hh
+++ b/src/OpenMesh/Core/IO/writer/BaseWriter.hh
@@ -78,7 +78,7 @@ namespace IO {
    Base class for all writer modules. The module should register itself at
    the IOManager by calling the register_module function.
 */
-class BaseWriter
+class OPENMESHDLLEXPORT BaseWriter
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/writer/OBJWriter.hh b/src/OpenMesh/Core/IO/writer/OBJWriter.hh
index c2264aad..3fd720a9 100644
--- a/src/OpenMesh/Core/IO/writer/OBJWriter.hh
+++ b/src/OpenMesh/Core/IO/writer/OBJWriter.hh
@@ -77,7 +77,7 @@ namespace IO {
     This class defines the OBJ writer. This class is further singleton'ed
     by SingletonT to OBJWriter.
 */
-class _OBJWriter_ : public BaseWriter
+class OPENMESHDLLEXPORT _OBJWriter_ : public BaseWriter
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/writer/OFFWriter.hh b/src/OpenMesh/Core/IO/writer/OFFWriter.hh
index 5a3d7bbd..780c8f59 100644
--- a/src/OpenMesh/Core/IO/writer/OFFWriter.hh
+++ b/src/OpenMesh/Core/IO/writer/OFFWriter.hh
@@ -89,7 +89,7 @@ namespace IO {
     ColorAlpha
 
 */
-class _OFFWriter_ : public BaseWriter
+class OPENMESHDLLEXPORT _OFFWriter_ : public BaseWriter
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/writer/OMWriter.hh b/src/OpenMesh/Core/IO/writer/OMWriter.hh
index c622d8f5..b00abfe4 100644
--- a/src/OpenMesh/Core/IO/writer/OMWriter.hh
+++ b/src/OpenMesh/Core/IO/writer/OMWriter.hh
@@ -86,7 +86,7 @@ class BaseExporter;
  *  Implementation of the OM format writer. This class is singleton'ed by 
  *  SingletonT to OMWriter.
  */
-class _OMWriter_ : public BaseWriter
+class OPENMESHDLLEXPORT _OMWriter_ : public BaseWriter
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/writer/PLYWriter.hh b/src/OpenMesh/Core/IO/writer/PLYWriter.hh
index f7267fcb..ad5df70d 100644
--- a/src/OpenMesh/Core/IO/writer/PLYWriter.hh
+++ b/src/OpenMesh/Core/IO/writer/PLYWriter.hh
@@ -83,7 +83,7 @@ namespace IO {
     - Binary
     - Binary -> MSB
 */
-class _PLYWriter_ : public BaseWriter
+class OPENMESHDLLEXPORT _PLYWriter_ : public BaseWriter
 {
 public:
 
diff --git a/src/OpenMesh/Core/IO/writer/STLWriter.hh b/src/OpenMesh/Core/IO/writer/STLWriter.hh
index 82eb99b0..11711266 100644
--- a/src/OpenMesh/Core/IO/writer/STLWriter.hh
+++ b/src/OpenMesh/Core/IO/writer/STLWriter.hh
@@ -81,7 +81,7 @@ namespace IO {
     Implementation of the STL format writer. This class is singleton'ed by 
     SingletonT to STLWriter.
 */
-class _STLWriter_ : public BaseWriter
+class OPENMESHDLLEXPORT _STLWriter_ : public BaseWriter
 {
 public: