bionic (3) aio_write.3posix.gz

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


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.1‐2008, <aio.h>


       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition,
       Standard  for  Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers,  Inc
       and  The  Open Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .

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       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 .