flux_timer_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_timer_watcher_create (flux_reactor_t *r,
                                           double after, double repeat,
                                           flux_watcher_f callback,
                                           void *arg);
void flux_timer_watcher_reset (flux_watcher_t *w,
                               double after, double repeat);

DESCRIPTION

flux_timer_watcher_create() creates a flux_watcher_t object which monitors for timer events. A timer event occurs when after seconds have elapsed, and optionally again every repeat seconds. When events occur, the user-supplied callback is invoked.

If after is 0., the flux_watcher_t will be immediately ready when the reactor is started. If repeat is 0., the flux_watcher_t will automatically be stopped when after seconds have elapsed.

Note that after is internally referenced to reactor time, which is only updated when the reactor is run/created, and therefore can be out of date. Use flux_reactor_now_update(3) to manually update reactor time before creating timer watchers in such cases. Refer to "The special problem of time updates" in the libev manual for more information.

To restart a timer that has been automatically stopped, you must reset the after and repeat values with flux_timer_watcher_reset() before calling flux_watcher_start().

The callback revents argument should be ignored.

Note: the Flux reactor is based on libev. For additional information on the behavior of timers, refer to the libev documentation on ev_timer.

RETURN VALUE

flux_timer_watcher_create() returns 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), flux_reactor_now(3)

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