The function epoll_wait is part of the epoll API in Linux, which is used for monitoring multiple file descriptors to see if they are ready for I/O operations. It allows applications to efficiently manage large numbers of connections by waiting for events on these file descriptors, such as incoming data or readiness to send data. When called, epoll_wait blocks until one or more events occur or a specified timeout is reached. It returns the number of file descriptors that are ready, allowing the application to handle them accordingly. This mechanism is particularly useful for high-performance network servers.