iofunc_write_verify()

Подтвердить наличие у клиента прав записи в ресурс

Прототип:

#include <sys/iofunc.h>
                                       
int iofunc_write_verify( resmgr_context_t *ctp,
                         io_write_t *msg,
                         iofunc_ocb_t *ocb,
                         int *nonblock );

Аргументы:

ctp

A pointer to a resmgr_context_t structure that the resource-manager library uses to pass context information between functions.

msg

A pointer to the io_write_t structure that contains the message that the resource manager received.

ocb

A pointer to the iofunc_ocb_t structure for the Open Control Block that was created when the client opened the resource.

nonblock

NULL, or a pointer to a location where the function can store a value that indicates whether or not the device is nonblocking:

• ≠0 — the client doesn't want to be blocked (i.e. O_NONBLOCK was set).
• 0 — the client wants to be blocked.

Библиотека:

libc

Описание:

The iofunc_write_verify() function checks that the client that sent the write message actually has write access to the resource, and, optionally (if nonblock isn't NULL), sets nonblock to O_NONBLOCK or 0.

The write permission check is done against ocb->ioflag.

Note that the io_write_t message has an override flag called msg->i.xtype. This flag allows the client to override the default blocking behavior for the resource on a per-request basis. This override flag is checked, and returned in the optional nonblock.

In write callout for your resource manager, you'll need to indicate how many bytes were written. You can do this with the macro:

_IO_SET_WRITE_NBYTES( resmgr_context_t *ctp, int nbytes )

Возвращаемое значение:

EOK

The client has write access to this resource.

EBADF

The client doesn't have write access to this resource.

Классификация:

ЗОСРВ «Нейтрино»

Точка остановки потока

Нет

Обработчик прерываний

Нет

Обработчик сигналов

Нет

В потоке

Да

Тематические ссылки:

io_write_t, iofunc_read_verify(), resmgr_context_t

Предыдущий раздел: Описание API системной библиотеки