инициировать список запросов ввода / вывода (initiate a list of I/O requests)
Имя (Name)
lio_listio - initiate a list of I/O requests
Синопсис (Synopsis)
#include <aio.h>
int lio_listio(int mode, struct aiocb *restrict const aiocb_list[restrict],
int nitems, struct sigevent *restrict sevp);
Link with -lrt.
Описание (Description)
The lio_listio() function initiates the list of I/O operations
described by the array aiocb_list.
The mode operation has one of the following values:
LIO_WAIT
The call blocks until all operations are complete. The
sevp argument is ignored.
LIO_NOWAIT
The I/O operations are queued for processing and the call
returns immediately. When all of the I/O operations
complete, asynchronous notification occurs, as specified
by the sevp argument; see sigevent(7) for details. If
sevp is NULL, no asynchronous notification occurs.
The aiocb_list argument is an array of pointers to aiocb
structures that describe I/O operations. These operations are
executed in an unspecified order. The nitems argument specifies
the size of the array aiocb_list. Null pointers in aiocb_list
are ignored.
In each control block in aiocb_list, the aio_lio_opcode field
specifies the I/O operation to be initiated, as follows:
LIO_READ
Initiate a read operation. The operation is queued as for
a call to aio_read(3) specifying this control block.
LIO_WRITE
Initiate a write operation. The operation is queued as
for a call to aio_write(3) specifying this control block.
LIO_NOP
Ignore this control block.
The remaining fields in each control block have the same meanings
as for aio_read(3) and aio_write(3). The aio_sigevent fields of
each control block can be used to specify notifications for the
individual I/O operations (see sigevent(7)).
Возвращаемое значение (Return value)
If mode is LIO_NOWAIT, lio_listio() returns 0 if all I/O
operations are successfully queued. Otherwise, -1 is returned,
and errno is set to indicate the error.
If mode is LIO_WAIT, lio_listio() returns 0 when all of the I/O
operations have completed successfully. Otherwise, -1 is
returned, and errno is set to indicate the error.
The return status from lio_listio() provides information only
about the call itself, not about the individual I/O operations.
One or more of the I/O operations may fail, but this does not
prevent other operations completing. The status of individual
I/O operations in aiocb_list can be determined using
aio_error(3). When an operation has completed, its return status
can be obtained using aio_return(3). Individual I/O operations
can fail for the reasons described in aio_read(3) and
aio_write(3).
Ошибки (Error)
The lio_listio() function may fail for the following reasons:
EAGAIN Out of resources.
EAGAIN The number of I/O operations specified by nitems would
cause the limit AIO_MAX to be exceeded.
EINTR mode was LIO_WAIT and a signal was caught before all I/O
operations completed; see signal(7). (This may even be
one of the signals used for asynchronous I/O completion
notification.)
EINVAL mode is invalid, or nitems exceeds the limit
AIO_LISTIO_MAX.
EIO One of more of the operations specified by aiocb_list
failed. The application can check the status of each
operation using aio_return(3).
If lio_listio() fails with the error EAGAIN, EINTR, or EIO, then
some of the operations in aiocb_list may have been initiated. If
lio_listio() fails for any other reason, then none of the I/O
operations has been initiated.
Версии (Versions)
The lio_listio() function is available since glibc 2.1.
Атрибуты (Attributes)
For an explanation of the terms used in this section, see
attributes(7).
┌──────────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────────┼───────────────┼─────────┤
│lio_listio() │ Thread safety │ MT-Safe │
└──────────────────────────────────────┴───────────────┴─────────┘
Стандарты (Conforming to)
POSIX.1-2001, POSIX.1-2008.
Примечание (Note)
It is a good idea to zero out the control blocks before use. The
control blocks must not be changed while the I/O operations are
in progress. The buffer areas being read into or written from
must not be accessed during the operations or undefined results
may occur. The memory areas involved must remain valid.
Simultaneous I/O operations specifying the same aiocb structure
produce undefined results.
Смотри также (See also)
aio_cancel(3), aio_error(3), aio_fsync(3), aio_return(3),
aio_suspend(3), aio_write(3), aio(7)
