aio_cancel.3, aio_error.3, aio_fsync.3, aio_read.3, aio_return.3, aio_suspend.3,...

[thirdparty/man-pages.git] / man3 / aio_write.3

.\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl)
.\"
.\" This is free documentation; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License as
.\" published by the Free Software Foundation; either version 2 of
.\" the License, or (at your option) any later version.
.\"
.\" The GNU General Public License's references to "object code"
.\" and "executables" are to be interpreted as the output of any
.\" document formatting or typesetting system, including
.\" intermediate and printed output.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
.\" GNU General Public License for more details.
.\"
.\" You should have received a copy of the GNU General Public
.\" License along with this manual; if not, write to the Free
.\" Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111,
.\" USA.
.\"
.TH AIO_WRITE 3 2010-10-02  "" "Linux Programmer's Manual"
.SH NAME
aio_write \- asynchronous write
.SH SYNOPSIS
.B "#include <aio.h>"
.sp
.BI "int aio_write(struct aiocb *" aiocbp );
.sp
Link with \fI\-lrt\fP.
.SH DESCRIPTION
The
.BR aio_write ()
function requests an asynchronous "n = write(fd, buf, count)"
with fd, buf, count given by
.IR aiocbp\->aio_fildes ,
.IR aiocbp\->aio_buf ,
.IR aiocbp\->aio_nbytes ,
respectively.
The return status n can be retrieved upon completion using
.BR aio_return (3).
.LP
If
.B O_APPEND
is not set, the data is written starting at the
absolute file offset
.IR aiocbp\->aio_offset ,
regardless of the current file position.
If
.B O_APPEND
is set, the data is written at the end of the file.
After this request, the value of the current file position is unspecified.
.LP
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
.BR aio_error (3).
.LP
If
.B _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
.IR aiocbp\->aio_reqprio .
.LP
The field
.I aiocbp\->aio_lio_opcode
is ignored.
.LP
No data is written to a regular file beyond its maximum offset.
.SH "RETURN VALUE"
On success, 0 is returned.
On error the request is not enqueued, \-1
is returned, and
.I errno
is set appropriately.
If an error is first detected later, it will
be reported via
.BR aio_return (3)
(returns status \-1) and
.BR aio_error (3)
(error status whatever one would have gotten in
.IR errno ,
such as
.BR EBADF ).
.SH ERRORS
.TP
.B EAGAIN
Out of resources.
.TP
.B EBADF
.I aio_fildes
is not a valid file descriptor open for writing.
.TP
.B 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.
.TP
.B EINVAL
One or more of
.IR aio_offset ,
.IR aio_reqprio ,
.I aio_nbytes
are invalid.
.TP
.B ENOSYS
This function is not supported.
.SH VERSIONS
The
.BR aio_write ()
function is available since glibc 2.1.
.SH "CONFORMING TO"
POSIX.1-2001, POSIX.1-2008.
.SH NOTES
It is a good idea to zero out the control block before use.
This control block must not be changed while the write operation
is in progress.
The buffer area being written out
.\" or the control block of the operation
must not be accessed during the operation or undefined results may
occur.
The memory areas involved must remain valid.
.SH "SEE ALSO"
.BR aio_cancel (3),
.BR aio_error (3),
.BR aio_fsync (3),
.BR aio_read (3),
.BR aio_return (3),
.BR aio_suspend (3),
.BR aio (7)