Manpage of AIO_WRITE

AIO_WRITE

Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
Index
 

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_nbytesof the structure pointed to by aiocbp. (See aio(7) for a description of the aiocbstructure.)

If O_APPENDis not set, the data is written starting at the absolute position aiocbp->aio_offset, regardless of the file offset. If O_APPENDis 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_sigeventappropriately; see sigevent(7) for details.

If _POSIX_PRIORITIZED_IOis 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_opcodeis 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 errnois 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_fildesis 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_nbytesare 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).
InterfaceAttributeValue
aio_write() Thread safetyMT-Safe
 

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 aiocbstructure 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)


 

Index

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
VERSIONS
ATTRIBUTES
CONFORMING TO
NOTES
SEE ALSO

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