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AIO_WRITE(3)                  Linux Programmer's Manual                  AIO_WRITE(3)

NAME         top

       aio_write - asynchronous write

SYNOPSIS         top

       #include <aio.h>

       int aio_write(struct aiocb *aiocbp);

       Link with -lrt.

DESCRIPTION         top

       The aio_write() function queues the I/O request described by the buffer
       pointed to by aiocb.  This function is the asynchronous analog of write(2).
       The arguments of the call

           write(fd, buf, count)

       correspond (in order) to the fields aio_fildes, aio_buf, and aio_nbytes of the
       structure pointed to by aiocbp.  (See aio(7) for a description of the aiocb
       structure.)

       If O_APPEND is not set, the data is written starting at the absolute file
       offset aiocbp->aio_offset, regardless of the current file offset.  If O_APPEND
       is set, data is written at the end of the file in the same order as
       aio_write() calls are made.  After the call, the value of the current file
       offset is unspecified.

       The "asynchronous" means that this call returns as soon as the request has
       been enqueued; the write may or may not have completed when the call returns.
       One tests for completion using aio_error(3).  The return status of a completed
       I/O operation can be obtained aio_return(3).  Asynchronous notification of I/O
       completion can be obtained by setting aiocbp->aio_sigevent appropriately; see
       sigevent(7) for details.

       If _POSIX_PRIORITIZED_IO is defined, and this file supports it, then the
       asynchronous operation is submitted at a priority equal to that of the calling
       process minus aiocbp->aio_reqprio.

       The field aiocbp->aio_lio_opcode is ignored.

       No data is written to a regular file beyond its maximum offset.

RETURN VALUE         top

       On success, 0 is returned.  On error the request is not enqueued, -1 is
       returned, and errno is set appropriately.  If an error is only detected later,
       it will be reported via aio_return(3) (returns status -1) and aio_error(3)
       (error status whatever one would have gotten in errno, such as EBADF).

ERRORS         top

       EAGAIN Out of resources.

       EBADF  aio_fildes is not a valid file descriptor open for writing.

       EFBIG  The file is a regular file, we want to write at least one byte, but the
              starting position is at or beyond the maximum offset for this file.

       EINVAL One or more of aio_offset, aio_reqprio, aio_nbytes are invalid.

       ENOSYS This function is not supported.

VERSIONS         top

       The aio_write() function is available since glibc 2.1.

CONFORMING TO         top

       POSIX.1-2001, POSIX.1-2008.

NOTES         top

       It is a good idea to zero out the control block before use.  The control block
       must not be changed while the write operation is in progress.  The buffer area
       being written out must not be accessed during the operation or undefined
       results may occur.  The memory areas involved must remain valid.

       Simultaneous I/O operations specifying the same aiocb structure produce
       undefined results.

SEE ALSO         top

       aio_cancel(3), aio_error(3), aio_fsync(3), aio_read(3), aio_return(3),
       aio_suspend(3), lio_listio(3), aio(7)

COLOPHON         top

       This page is part of release 3.32 of the Linux man-pages project.  A
       description of the project, and information about reporting bugs, can be found
       at http://www.kernel.org/doc/man-pages/.

                                      2010-10-02                         AIO_WRITE(3)

HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface

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