aio_write

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



NAME
       aio_write - asynchronous write

SYNOPSIS
       #include <aio.h>

       int aio_write(struct aiocb *aiocbp);

       Link with -lrt.

DESCRIPTION
       The aio_write() function queues the I/O request described by the buffer
       pointed to by aiocbp.  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
       position aiocbp->aio_offset, regardless of the 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
       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
       On success, 0 is returned.  On error, the request is not enqueued, -1
       is returned, and errno is set appropriately.  If an error is detected
       only 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
       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 aio_write() is not implemented.

VERSIONS
       The aio_write() function is available since glibc 2.1.

ATTRIBUTES
       For an explanation of the terms used in this section, see
       attributes(7).

       ┌────────────┬───────────────┬─────────┐
       │Interface   Attribute     Value   │
       ├────────────┼───────────────┼─────────┤
       │aio_write() │ Thread safety │ MT-Safe │
       └────────────┴───────────────┴─────────┘
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008.

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

COLOPHON
       This page is part of release 5.03 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.



                                  2017-09-15                      AIO_WRITE(3)