fi_trywait(3) on Linux
The text bbc158fdbafd, as Debian 9 (Stretch) shipped it.
Polling and wait set operations fi_poll_open / fi_close : Open/close a polling set fi_poll_add / fi_poll_del : Add/remove a completion queue or counter to/from a poll set. fi_poll : Poll for progress and events across multiple completion queues and counters. fi_wait_open / fi_close : Open/close a wait set fi_wait : Waits for one or more wait objects in a set to be signaled. fi_trywait : Indicate when it is safe to block on wait objects using native OS calls. fi_control : Control wait set operation or attributes.