структура для уведомления от асинхронных подпрограмм (structure for notification from asynchronous routines)
Имя (Name)
sigevent - structure for notification from asynchronous routines
Синопсис (Synopsis)
#include <signal.h>
union sigval { /* Data passed with notification */
int sival_int; /* Integer value */
void *sival_ptr; /* Pointer value */
};
struct sigevent {
int sigev_notify; /* Notification method */
int sigev_signo; /* Notification signal */
union sigval sigev_value;
/* Data passed with notification */
void (*sigev_notify_function)(union sigval);
/* Function used for thread
notification (SIGEV_THREAD) */
void *sigev_notify_attributes;
/* Attributes for notification thread
(SIGEV_THREAD) */
pid_t sigev_notify_thread_id;
/* ID of thread to signal
(SIGEV_THREAD_ID); Linux-specific */
};
Описание (Description)
The sigevent structure is used by various APIs to describe the
way a process is to be notified about an event (e.g., completion
of an asynchronous request, expiration of a timer, or the arrival
of a message).
The definition shown in the SYNOPSIS is approximate: some of the
fields in the sigevent structure may be defined as part of a
union. Programs should employ only those fields relevant to the
value specified in sigev_notify.
The sigev_notify field specifies how notification is to be
performed. This field can have one of the following values:
SIGEV_NONE
A "null" notification: don't do anything when the event
occurs.
SIGEV_SIGNAL
Notify the process by sending the signal specified in
sigev_signo.
If the signal is caught with a signal handler that was
registered using the sigaction(2) SA_SIGINFO flag, then
the following fields are set in the siginfo_t structure
that is passed as the second argument of the handler:
si_code
This field is set to a value that depends on the
API delivering the notification.
si_signo
This field is set to the signal number (i.e., the
same value as in sigev_signo).
si_value
This field is set to the value specified in
sigev_value.
Depending on the API, other fields may also be set in the
siginfo_t structure.
The same information is also available if the signal is
accepted using sigwaitinfo(2).
SIGEV_THREAD
Notify the process by invoking sigev_notify_function "as
if" it were the start function of a new thread. (Among
the implementation possibilities here are that each timer
notification could result in the creation of a new thread,
or that a single thread is created to receive all
notifications.) The function is invoked with sigev_value
as its sole argument. If sigev_notify_attributes is not
NULL, it should point to a pthread_attr_t structure that
defines attributes for the new thread (see
pthread_attr_init(3)).
SIGEV_THREAD_ID (Linux-specific)
Currently used only by POSIX timers; see timer_create(2).
Смотри также (See also)
timer_create(2), aio_fsync(3), aio_read(3), aio_write(3),
getaddrinfo_a(3), lio_listio(3), mq_notify(3), aio(7),
pthreads(7)
