lio_listio(3) - NetBSD Manual Pages

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LIO_LISTIO(3)           NetBSD Library Functions Manual          LIO_LISTIO(3)


NAME

     lio_listio -- list directed I/O (REALTIME)


LIBRARY

     POSIX Real-time Library (librt, -lrt)


SYNOPSIS

     #include <aio.h>

     int
     lio_listio(int mode, struct aiocb * const list[], int nent,
         struct sigevent *sig);


DESCRIPTION

     The lio_listio() function initiates a list of I/O requests with a single
     function call.  The list argument is an array of pointers to aiocb struc-
     tures describing each operation to perform, with nent elements.  NULL
     elements are ignored.

     The aio_lio_opcode field of each aiocb specifies the operation to be per-
     formed.  The following operations are supported:

           LIO_READ   Read data as if by a call to aio_read(3).

           LIO_NOP    No operation.

           LIO_WRITE  Write data as if by a call to aio_write(3).

     If the mode argument is LIO_WAIT, lio_listio() does not return until all
     the requested operations have been completed.  If mode is LIO_NOWAIT, the
     requests are processed asynchronously, and the signal specified by sig is
     sent when all operations have completed.  If sig is NULL, the calling
     process is not notified of I/O completion.

     The order in which the requests are carried out is not specified, and
     there is no guarantee that they will be executed sequentially.


RETURN VALUES

     If mode is LIO_WAIT, the lio_listio() function returns 0 if the opera-
     tions completed successfully, otherwise -1.

     If mode is LIO_NOWAIT, the lio_listio() function returns 0 if the opera-
     tions are successfully queued, otherwise -1.


ERRORS

     The lio_listio() function will fail if:

     [EAGAIN]           There are not enough resources to enqueue the
                        requests; or the request would cause the system-wide
                        limit AIO_MAX to be exceeded.

     [EINTR]            A signal interrupted the system call before it could
                        be completed.

     [EINVAL]           The mode argument is neither LIO_WAIT nor LIO_NOWAIT,
                        or nent is greater than AIO_LISTIO_MAX.

     [EIO]              One or more requests failed.

     In addition, the lio_listio() function may fail for any of the reasons
     listed for aio_read(3) and aio_write(3).

     If lio_listio() succeeds, or fails with an error code of EAGAIN, EINTR,
     or EIO, some of the requests may have been initiated.  The caller should
     check the error status of each aiocb structure individually by calling
     aio_error(3).


SEE ALSO

     read(2), siginfo(2), write(2), aio(3), sigevent(3)


STANDARDS

     The lio_listio() function is expected to conform to IEEE Std 1003.1-2001
     (``POSIX.1'').

NetBSD 9.2                      August 12, 2011                     NetBSD 9.2