Modifies a pointer to a Context to point to a different Context.
The modification is done atomically (so this is useful for ensuring thread safety in some cases), and the reference counts are updated appropriately (the old context is unreffed, the new one is reffed).
Either new_context
or the Context pointed to by old_context
may be
null
.
old_context |
pointer to a pointer to a Context to be replaced. |
new_context |
pointer to a Context that will replace the context pointed to by |
|