Example One

/*! 
 * \brief Park a call
 * \param chan channel parking the call
 * \param peer call leg to be parked
 * \param timeout hold time until call returns to 'out exten'
 * \param extout extension to return to after timeout
 * Lock the parkinglot list, look for a free parking lot,
 * setup callback for when timeout ia reached, place call in parking context
 * create manager event, check see if timeout is reached.
 * \note We put the user in the parking list, then wake up the 
 * parking thread to be sure it looks after these channels too 
 * \retval 0 on success.
 * \retval -1 on failure.
*/
int ast_park_call(struct ast_channel *chan, struct ast_channel *peer, int timeout, int *extout)

Example Two

/*!
 * \brief masqurade a call to be parked
 * \param rchan channel parking a call
 * \param peer channel to be parked
 * \param timeout how long to stay parked
 * \param extout extension to call after timeout
 * This function creates a new channel, stores which context/extension was called from
 * then calls park_call to finish up.
 * \retval 0 on success.
 * \retval -1 on failure.
*/
int ast_masq_park_call(struct ast_channel *rchan, struct ast_channel *peer, int timeout, int *extout)