diff --git a/docs/doc-geo.txt b/docs/doc-geo.txt
index ac0c758..bc6365d 100644
--- a/docs/doc-geo.txt
+++ b/docs/doc-geo.txt
@@ -35,6 +35,17 @@ Functions
             
             unsigned int, for quantity of coordinates to be printed.
 
+    bool getheader(struct Header**, const char*);
+        Retrieves the header for a geometry package.
+
+            input:
+                Pointer of a pointer to struct Header.
+                Pass by reference of a pointer to the function.
+                The pointer of Header can be NULL and will be set to point to
+                a region in the buffer.
+
+                const char*, file data
+                Can not be NULL.
 
     bool getmeshheader(struct MeshHeader**, 
                        unsigned int,