egd_start man page
egd_start, egd_stop — start and stop buffered acquisition
int egd_start(struct eegdev* dev);
int egd_stop(struct eegdev* dev);
egd_start() marks the beginning of buffered acquisition from the device referenced by dev. This means that the data starts getting accumulated in an internal ringbuffer and this buffered data can be sequentially obtained by successive calls to egd_get_data(3). A buffered acquisition started implies that the user has to get the data often enough to prevent the situation of a full ringbuffer.
egd_stop() halts the buffered acquisition of the device referenced by dev, relieving the user from the obligation to get data regularly.
The function returns 0 in case of succes. Otherwise, -1 is returned and errno is set accordingly.
egd_start() and egd_stop() will fail if:
dev is NULL.
egd_stop(3) is an alias of egd_start(3).