-const std::string GDCM_UNFOUND = "gdcm::Unfound";
-const std::string GDCM_BINLOADED = "gdcm::Binary data loaded";
-const std::string GDCM_NOTLOADED = "gdcm::NotLoaded";
-const std::string GDCM_UNREAD = "gdcm::UnRead";
-
-/// \brief TagKey is made to hold an "universal" (as in URL, Universal
-/// Ressource Locator) key to a DocEntry i.e. a dicom tag.
-/// A dicom tag always has a group and an element, but a set of tags
-/// embeded in various (optionally nested) sequences and sharing
-/// the same group and element all share the same (group, element)
-/// "identifier". Hence the (group, element) cannot be used as an
-/// identifier (in gdcm we shall refer to a "TagKey") of a tag.
-/// In order to construct a proper tag identifier (i.e. a key) we
-/// consider the following definition of a TagKey:
-/// - let Group, Element be the string representation of the
-/// group and element dicom tag members,
-/// - let ItemNumber be the string representation of the integer
-/// index of the considered item number of a sequence,
-/// Let the key of a tag embeded in a sequence, noted SeqTag, be
-/// the form:
-/// /ItemNumber#Group|Element
-/// where "/", "#" and "|" are characters acting as separators.
-/// Then the general form of a TagKey is given by:
-/// Group|Element[SeqTag]
-/// where [SeqTag] means NO or many instances of SeqTag.
-/// Hence the TagKey of a tag not "leaving" in a sequence is the
-/// string e.g.
-/// 0028|1201
-/// but the TagKey of a tag "embeded" is the first item of
-/// a sequence, itself nested in the third item of a sequence is the
-/// string e.g.
-/// 0004|1220/2#0008|0082/0#0008|0090
-typedef std::string TagKey;
+GDCM_EXPORT extern const char GDCM_VRUNKNOWN[2];
+
+GDCM_EXPORT extern const char GDCM_FILESEPARATOR;
+
+/// \brief TagKey is made to hold the standard Dicom Tag
+/// (Group number, Element number)
+/// Instead of using the two '16 bits integers' as the Hask Table key, we
+/// converted into a string (e.g. 0x0018,0x0050 converted into "0018|0050")
+/// It appears to be a huge waste of time.
+/// We'll fix the mess up -without any change in the API- as soon as the bench
+/// marks are fully performed.
+
+#if defined(_MSC_VER) && (_MSC_VER == 1200)
+// Doing everything within gdcm namespace to avoid polluting 3d party software
+inline std::ostream& operator<<(std::ostream& _O, std::string _val)
+{
+ return _O << _val.c_str();
+}
+#endif
+
+/// \brief TagName is made to hold the 'non hexa" fields (VR, VM, Name)
+/// of Dicom Entries