Depends on what rigging is attached to it, the diameter, and a whole lot of
other factors. Generally, you have two choices:
1. Completely replace it and redo all the rigging.
2. Drill a small long, hole, very carefully, down the center of both
matching pieces. The way to get the alignment perfect is to drill one side,
and the to place the drill, sharp point out, sticking out about 1/16" or so.
Then align the two pieces and push. Now you've marked the second part of
the mast. Drill that out. Then insert a piece of piano wire and glue the
parts together. After the glue sets, refinish to hide the repair.
Glue without re-enforcement of the wire will not stand up to the strain of