aio_write(3) - Linux manual page (original) (raw)

aiowrite(3) Library Functions Manual aiowrite(3)

NAME top

   aio_write - asynchronous write

LIBRARY top

   Real-time library (_librt_, _-lrt_)

SYNOPSIS top

   **#include <aio.h>**

   **int aio_write(struct aiocb ***_aiocbp_**);**

DESCRIPTION top

   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)](../man2/write.2.html).  The arguments of the call

       write(fd, buf, count)

   correspond (in order) to the fields _aiofildes_, _aiobuf_, and
   _aionbytes_ of the structure pointed to by _aiocbp_.  (See [aio(7)](../man7/aio.7.html) for
   a description of the _aiocb_ structure.)

   If **O_APPEND** is not set, the data is written starting at the
   absolute position _aiocbp->aiooffset_, 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)](../man3/aio%5Ferror.3.html).  The return status of a completed I/O operation can
   be obtained [aio_return(3)](../man3/aio%5Freturn.3.html).  Asynchronous notification of I/O
   completion can be obtained by setting _aiocbp->aiosigevent_
   appropriately; see [sigevent(3type)](../man3/sigevent.3type.html) 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->aioreqprio_.

   The field _aiocbp->aiolioopcode_ 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](../man3/errno.3.html)_ is set to indicate the error.  If an
   error is detected only later, it will be reported via
   [aio_return(3)](../man3/aio%5Freturn.3.html) (returns status -1) and [aio_error(3)](../man3/aio%5Ferror.3.html) (error status—
   whatever one would have gotten in _[errno](../man3/errno.3.html)_, such as **EBADF**).

ERRORS top

   **EAGAIN** Out of resources.

   **EBADF** _aiofildes_ 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 _aiooffset_, _aioreqprio_, _aionbytes_ are
          invalid.

   **ENOSYS aio_write**() is not implemented.

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────────────────────────────┬───────────────┬─────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────────────────────────────┼───────────────┼─────────┤
   │ **aio_write**()                          │ Thread safety │ MT-Safe │
   └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS top

   POSIX.1-2008.

HISTORY top

   glibc 2.1.  POSIX.1-2001.

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)](../man3/aio%5Fcancel.3.html), [aio_error(3)](../man3/aio%5Ferror.3.html), [aio_fsync(3)](../man3/aio%5Ffsync.3.html), [aio_read(3)](../man3/aio%5Fread.3.html),
   [aio_return(3)](../man3/aio%5Freturn.3.html), [aio_suspend(3)](../man3/aio%5Fsuspend.3.html), [lio_listio(3)](../man3/lio%5Flistio.3.html), [aio(7)](../man7/aio.7.html)

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Linux man-pages 6.10 2024-07-23 aiowrite(3)

Pages that refer to this page:execve(2), fork(2), aio_cancel(3), aiocb(3type), aio_error(3), aio_fsync(3), aio_read(3), aio_return(3), aio_suspend(3), lio_listio(3), aio(7)