next

Get the next item from the iterator in elem.

Only when this function returns gst_iterator_ok, elem will contain a valid value. elem must have been initialized to the type of the iterator or initialized to zeroes with unset. The caller is responsible for unsetting or resetting elem with unset or reset after usage.

When this function returns gst_iterator_done, no more elements can be retrieved from this.

A return value of gst_iterator_resync indicates that the element list was concurrently updated. The user of this should call resync to get the newly updated list.

A return value of gst_iterator_error indicates an unrecoverable fatal error.

Parameters:

this	The Iterator to iterate
elem	pointer to hold next element

Returns:

The result of the iteration. Unset elem after usage. MT safe.