flux_fd_watcher_create(3)
SYNOPSIS
#include <flux/core.h>
typedef void (*flux_watcher_f)(flux_reactor_t *r,
flux_watcher_t *w,
int revents,
void *arg);
flux_watcher_t *flux_fd_watcher_create (flux_reactor_t *r,
int fd,
int events,
flux_watcher_f callback,
void *arg);
int flux_fd_watcher_get_fd (flux_watcher_t *w);
Link with -lflux-core.
DESCRIPTION
flux_fd_watcher_create()
creates a flux_watcher_t
object which
can be used to monitor for events on a file descriptor fd
. When events
occur, the user-supplied callback
is invoked.
The events
and revents
arguments are a bitmask containing a
logical OR of the following bits. If a bit is set in events
, it
indicates interest in this type of event. If a bit is set in revents
, it
indicates that this event has occurred.
- FLUX_POLLIN
The file descriptor is ready for reading.
- FLUX_POLLOUT
The file descriptor is ready for writing.
- FLUX_POLLERR
The file descriptor has encountered an error. This bit is ignored if it is set in the create events argument.
Events are processed in a level-triggered manner. That is, the callback will continue to be invoked as long as the event has not been fully consumed or cleared, and the watcher has not been stopped.
flux_fd_watcher_get_fd()
is used to obtain the file descriptor from
within the flux_watcher_f callback
.
RETURN VALUE
flux_fd_watcher_create()
returns a flux_watcher_t
object on
success. On error, NULL is returned, and errno
is set appropriately.
flux_fd_watcher_get_fd()
returns the file descriptor associated with
the watcher.
ERRORS
- ENOMEM
Out of memory.
RESOURCES
Flux: http://flux-framework.org
Flux RFC: https://flux-framework.readthedocs.io/projects/flux-rfc
Issue Tracker: https://github.com/flux-framework/flux-core/issues