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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 file offset
aiocbp->aio_offset, regardless of the current 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 current 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.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
NOTES
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
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 3.74 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 http://www.kernel.org/doc/man-pages/.
2012-05-08 AIO_WRITE(3)
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