flux_idle_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_prepare_watcher_create (flux_reactor_t *r,
                                             flux_watcher_f callback,
                                             void *arg);
flux_watcher_t *flux_check_watcher_create (flux_reactor_t *r,
                                           flux_watcher_f callback,
                                           void *arg);
flux_watcher_t *flux_idle_watcher_create (flux_reactor_t *r,
                                          flux_watcher_f callback,
                                          void *arg);

DESCRIPTION

flux_prepare_watcher_create(), flux_check_watcher_create(), and flux_idle_watcher_create() create specialized reactor watchers with the following properties:

The prepare watcher is called by the reactor loop immediately before blocking, while the check watcher is called by the reactor loop immediately after blocking.

The idle watcher is always run when no other events are pending, excluding other idle watchers, prepare and check watchers. While it is active, the reactor loop does not block waiting for new events.

The callback revents argument should be ignored.

Note: the Flux reactor is based on libev. For additional information on the behavior of these watchers, refer to the libev documentation on ev_idle, ev_prepare, and ev_check.

RETURN VALUE

These functions return a flux_watcher_t object on success. On error, NULL is returned, and errno is set appropriately.

ERRORS

ENOMEM
Out of memory.

SEE ALSO

flux_watcher_start(3), flux_reactor_start(3)

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