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



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

NAME
       aio_write -- asynchronous write to a file

SYNOPSIS
       #include <aio.h>

       int aio_write(struct aiocb *aiocbp);

DESCRIPTION
       The aio__write() function shall write aiocbp->aio__nbytes to the file
       associated with aiocbp->aio__fildes from the buffer pointed to by
       aiocbp->aio__buf. The function shall return when the write request has
       been initiated or, at a minimum, queued to the file or device.

       If prioritized I/O is supported for this file, then the asynchronous
       operation shall be submitted at a priority equal to a base scheduling
       priority minus aiocbp->aio__reqprio. If Thread Execution Scheduling is
       not supported, then the base scheduling priority is that of the calling
       process;
       otherwise, the base scheduling priority is that of the calling thread.

       The aiocbp argument may be used as an argument to aio__error() and
       aio__return() in order to determine the error status and return status,
       respectively, of the asynchronous operation while it is proceeding.

       The aiocbp argument points to an aiocb structure. If the buffer pointed
       to by aiocbp->aio__buf or the control block pointed to by aiocbp becomes
       an illegal address prior to asynchronous I/O completion, then the
       behavior is undefined.

       If O_APPEND is not set for the file descriptor aio__fildes, then the
       requested operation shall take place at the absolute position in the
       file as given by aio__offset, as if lseek() were called immediately
       prior to the operation with an offset equal to aio__offset and a whence
       equal to SEEK_SET.  If O_APPEND is set for the file descriptor, or if
       aio__fildes is associated with a device that is incapable of seeking,
       write operations append to the file in the same order as the calls were
       made, except under circumstances described in Section 2.8.2,
       Asynchronous I/O.  After a successful call to enqueue an asynchronous
       I/O operation, the value of the file offset for the file is
       unspecified.

       The aio__sigevent member specifies the notification which occurs when
       the request is completed.

       The aiocbp->aio__lio__opcode field shall be ignored by aio__write().

       Simultaneous asynchronous operations using the same aiocbp produce
       undefined results.

       If synchronized I/O is enabled on the file associated with
       aiocbp->aio__fildes, the behavior of this function shall be according to
       the definitions of synchronized I/O data integrity completion, and
       synchronized I/O file integrity completion.

       For any system action that changes the process memory space while an
       asynchronous I/O is outstanding to the address range being changed, the
       result of that action is undefined.

       For regular files, no data transfer shall occur past the offset maximum
       established in the open file description associated with
       aiocbp->aio__fildes.

RETURN VALUE
       The aio__write() function shall return the value zero if the I/O
       operation is successfully queued; otherwise, the function shall return
       the value -1 and set errno to indicate the error.

ERRORS
       The aio__write() function shall fail if:

       EAGAIN The requested asynchronous I/O operation was not queued due to
              system resource limitations.

       Each of the following conditions may be detected synchronously at the
       time of the call to aio__write(), or asynchronously. If any of the
       conditions below are detected synchronously, the aio__write() function
       shall return -1 and set errno to the corresponding value. If any of the
       conditions below are detected asynchronously, the return status of the
       asynchronous operation shall be set to -1, and the error status of the
       asynchronous operation is set to the corresponding value.

       EBADF  The aiocbp->aio__fildes argument is not a valid file descriptor
              open for writing.

       EINVAL The file offset value implied by aiocbp->aio__offset would be
              invalid,
              aiocbp->aio__reqprio is not a valid value, or aiocbp->aio__nbytes
              is an invalid value.

       In the case that the aio__write() successfully queues the I/O operation,
       the return status of the asynchronous operation shall be one of the
       values normally returned by the write() function call. If the operation
       is successfully queued but is subsequently canceled or encounters an
       error, the error status for the asynchronous operation contains one of
       the values normally set by the write() function call, or one of the
       following:

       EBADF  The aiocbp->aio__fildes argument is not a valid file descriptor
              open for writing.

       EINVAL The file offset value implied by aiocbp->aio__offset would be
              invalid.

       ECANCELED
              The requested I/O was canceled before the I/O completed due to
              an explicit aio__cancel() request.

       The following condition may be detected synchronously or
       asynchronously:

       EFBIG  The file is a regular file, aiobcp->aio__nbytes is greater than
              0, and the starting offset in aiobcp->aio__offset is at or beyond
              the offset maximum in the open file description associated with
              aiocbp->aio__fildes.

       The following sections are informative.

EXAMPLES
       None.

APPLICATION USAGE
       None.

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       Section 2.8.2, Asynchronous I/O, aio__cancel(), aio__error(), aio__read(),
       aio__return(), close(), exec, exit(), fork(), lio__listio(), lseek(),
       write()

       The Base Definitions volume of POSIX.1-2017, <aio.h>

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  In the event of any discrepancy between this version and the
       original IEEE and The Open Group Standard, the original IEEE and The
       Open Group Standard is the referee document. The original Standard can
       be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                         AIO_WRITE(3)
