sendTags: communicate specified tag to all processors sharing
entities owned by this processor 

- by tag
- by type/topology
- by entity(ies)
- by destination part

    /**\brief  Asynchronously exchange tag data for entity type/topo
     * and part
     *
     * Exchange tag information for shared entities of specified type/
     * topology to specified part.  This version operates on all
     * shared entities of specified type/topology (or all
     * types/topologies if iMesh_ALL_TYPE or iMesh_ALL_TOPOLOGIES are
     * given).  This function assumes tag handles given on various
     * calling parts are consistent, i.e. they have the same name,
     * data type, size, etc.  Applications can call prefix_Wait or
     * prefix_WaitEnt to block until associated call completes
     * \param tag Tag handle to exchange
     * \param ent_type Tag data exchanged only for this entity type
     * \param ent_topo Tag data exchanged only for this entity topology
     * \param to_part Tag info exchanged only with this part
     * \param prefix_Request Request object used in call to
     *    prefix_Wait or prefixWaitEnt
     * \param err Error returned from function
     */
prefix_IExchTags(/*in*/ TagHandle tag, 
                 /*in*/ EntityType ent_type, 
                 /*in*/ EntityTopology ent_topo, 
                 /*in*/ PartHandle to_part, 
                 /*out*/ prefix_Request *req,
                 /*out*/ int *err)

    /**\brief  Asynchronously exchange tag data for entities and part
     *
     * Exchange tag information for specified entities, which must
     * already be shared.  This function assumes tag handles given on various
     * calling parts are consistent, i.e. they have the same name,
     * data type, size, etc.  Applications can call prefix_Wait or
     * prefix_WaitEnt to block until associated call completes
     * \param tag Tag handle to exchange
     * \param entities Entities for which to exchange data
     * \param entities_size Number of entities
     * \param to_part Tag info exchanged only with this part
     * \param prefix_Request Request object used in call to
     *    prefix_Wait or prefixWaitEnt
     * \param err Error returned from function
     */
prefix_IExchTagsEnt(/*in*/ TagHandle tag, 
                    /*in*/ EntityHandle *entities,
                    /*in*/ int entities_size,
                    /*in*/ PartHandle to_part, 
                    /*out*/ prefix_Request *req,
                    /*out*/ int *err)

    /**\brief  Synchronously exchange tag data for entity type/topo
     * and part
     *
     * Exchange tag information for shared entities of specified type/
     * topology to specified part.  This version operates on all
     * shared entities of specified type/topology (or all
     * types/topologies if iMesh_ALL_TYPE or iMesh_ALL_TOPOLOGIES are
     * given).  This function assumes tag handles given on various
     * calling parts are consistent, i.e. they have the same name,
     * data type, size, etc.  This call blocks until communication is
     * completed
     * \param tag Tag handle to exchange
     * \param ent_type Tag data exchanged only for this entity type
     * \param ent_topo Tag data exchanged only for this entity topology
     * \param to_part Tag info exchanged only with this part
     * \param err Error returned from function
     */
prefix_ExchTags(/*in*/ TagHandle tag, 
                /*in*/ EntityType ent_type, 
                /*in*/ EntityTopology ent_topo, 
                /*in*/ PartHandle to_part,
                /*out*/ int *err)

    /**\brief  Synchronously exchange tag data for entities and part
     *
     * Exchange tag information for specified entities, which must
     * already be shared.  This function assumes tag handles given on various
     * calling parts are consistent, i.e. they have the same name,
     * data type, size, etc.  This call blocks until communication is
     * completed
     * \param tag Tag handle to exchange
     * \param entities Entities for which to exchange data
     * \param entities_size Number of entities
     * \param to_part Tag info exchanged only with this part
     * \param err Error returned from function
     */
prefix_ExchTagsEnt(/*in*/ TagHandle tag, 
                   /*in*/ EntityHandle *entities,
                   /*in*/ int entities_size,
                   /*in*/ PartHandle to_part,
                   /*out*/ int *err)

    /**\brief  Wait for specified request to complete
     *
     * Wait for the specified request to complete.
     * \param req Request object to wait on
     * \param stat Status of communication request
     * \param err Error returned from function
     */
prefix_Wait(/*in*/ prefix_Request req,
            /*out*/ prefix_Status stat,
            /*out*/ int *err)

    /**\brief  Wait for any of the specified requests to complete
     *
     * Wait for any of the specified requests to complete.
     * \param req Request objects to wait on
     * \param req_size Number of request objects
     * \param index Index of request in req which was completed
     * \param stat Status of communication request
     * \param err Error returned from function
     */
prefix_WaitAny(/*in*/ prefix_Request *req,
               /*in*/ int req_size,
               /*out*/ int *index,
               /*out*/ prefix_Status *stat,
               /*out*/ int *err)

    /**\brief  Wait for specified request to complete
     *
     * Wait for the specified request to complete.  Returns entities
     * for which information was \em received
     * \param req Request object to wait on
     * \param entities Entities for which information was received
     * \param entities_alloc Allocated size of entities vector
     * \param entities_size Occupied size of entities vector
     * \param err Error returned from function
     */
prefix_WaitEnt(/*in*/ prefix_Request req,
               /*inout*/ EntityHandle **out_entities,
               /*inout*/ int *out_entities_alloc,
               /*inout*/ int *out_entities_size,
               /*out*/ int *err)

    /**\brief Test for whether specified request has completed
     *
     * Test for whether specified request has completed
     * \param req Request objects to wait on
     * \param flag Returned true if request completed
     * \param stat Status of communication request
     * \param err Error returned from function
     */
prefix_Test(/*in*/ prefix_Request req,
            /*out*/ int *flag,
            /*out*/ prefix_Status *stat,
            /*out*/ int *err)