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man pages section 3: Extended Library Functions, Volume 4

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Updated: Thursday, June 13, 2019
 
 

sysevent_unbind_handle(3SYSEVENT)

Name

sysevent_bind_handle, sysevent_unbind_handle - bind or unbind subscriber handle

Synopsis

cc [flag…]  file–lsysevent [library …] 
#include <libsysevent.h>

sysevent_handle_t *sysevent_bind_handle(void (*event_handler)
     (sysevent_t *ev));
void sysevent_unbind_handle(sysevent_handle_t *sysevent_hdl);

Parameters

ev

pointer to sysevent buffer handle

event_handler

pointer to an event handling function

sysevent_hdl

pointer to a sysevent subscriber handle

Description

The sysevent_bind_handle() function allocates memory associated with a subscription handle and binds it to the caller's event_handler. The event_handler is invoked during subsequent system event notifications once a subscription has been made with sysevent_subscribe_event(3SYSEVENT).

The system event is represented by the argument ev and is passed as an argument to the invoked event delivery function, event_handler.

Additional threads are created to service communication between syseventd(8) and the calling process and to run the event handler routine, event_handler .

The sysevent_unbind_handle() function deallocates memory and other resources associated with a subscription handle and deactivates all system event notifications for the calling process. All event notifications are guaranteed to stop upon return from sysevent_unbind_handle ().

Return Values

The sysevent_bind_handle() function returns a valid sysevent subscriber handle if the handle is successfully allocated. Otherwise, NULL is returned and errno is set to indicate the error.

The sysevent_unbind_handle() function returns no value.

Errors

The sysevent_bind_handle() function will fail if:

EACCES

The calling process has an ID other than the privileged user.

EBUSY

There are no resources available.

EINVAL

The pointer to the function event_handler is NULL.

EMFILE

The process has too many open descriptors.

ENOMEM

There are insufficient resources to allocate the handle.

Attributes

See attributes(7) for descriptions of the following attributes:

ATTRIBUTE TYPE
ATTRIBUTE VALUE
Interface Stability
Committed
MT-Level
MT-Safe

See Also

sysevent_subscribe_event(3SYSEVENT), attributes(7), syseventd(8)

Notes

Event notifications are revoked by syseventd when the bound process dies. Event notification is suspended if a signal is caught and handled by the event_handler thread. Event notification is also suspended when the calling process attempts to use fork(2) or fork1(2). Event notifications might be lost during suspension periods.

The libsysevent interfaces do not work at all in non-global zones.