7.7
eventfd
Jan Dvořák <mordae@anilinux.org>
Linux eventfd interface for Racket.
| (require eventfd) | package: eventfd |
Interface that allows manipulation of Linux eventfd descriptors in a way similar to Racket’s semaphores.
Predicate identifying an event descriptor structure.
These event descriptors also act as a synchronizable event that
produces same results as eventfd-wait would.
procedure
(eventfd initial-value [ #:semaphore? semaphore?]) → eventfd? initial-value : exact-nonnegative-integer? semaphore? : boolean? = #f
Create completely new event descriptor.
Remember that these count towards process file descriptor count.
procedure
(fd->eventfd fd) → eventfd?
fd : exact-nonnegative-integer?
Create an eventfd? structure for an existing descriptor.
It is undefined what happens when you pass it something that is not a
valid event descriptor.
procedure
(eventfd-post efd [value]) → void?
efd : eventfd? value : exact-nonnegative-integer? = 1
Post given value to the semaphore.
procedure
efd : eventfd?
Wait until the semaphore represented by the descriptor becomes
higher than zero and then return either it’s value, resetting it back
to zero (when #:semaphore? set to #f) or return just
1, decrementing the semaphore.
procedure
(eventfd-fd efd) → exact-nonnegative-integer?
efd : eventfd?
Return event descriptor as an integer.