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 con-
       trol block must	not  be	 changed  while	 the  write  operation	is  in
       progress.   The buffer area being written out must not be accessed dur-
       ing 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 4.10 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/.



				  2016-03-15			  AIO_WRITE(3)