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PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
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AIO_WRITE(3P) POSIX Programmer's Manual AIO_WRITE(3P)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
aio_write — asynchronous write to a file
#include <aio.h>
int aio_write(struct aiocb *aiocbp);
The aio_write() function shall write aiocbp->aio_nbytes to the
file associated with aiocbp->aio_fildes from the buffer pointed to
by aiocbp->aio_buf. The function shall return when the write
request has been initiated or, at a minimum, queued to the file or
device.
If prioritized I/O is supported for this file, then the
asynchronous operation shall be submitted at a priority equal to a
base scheduling priority minus aiocbp->aio_reqprio. If Thread
Execution Scheduling is not supported, then the base scheduling
priority is that of the calling process;
otherwise, the base scheduling priority is that of the calling
thread.
The aiocbp argument may be used as an argument to aio_error() and
aio_return() in order to determine the error status and return
status, respectively, of the asynchronous operation while it is
proceeding.
The aiocbp argument points to an aiocb structure. If the buffer
pointed to by aiocbp->aio_buf or the control block pointed to by
aiocbp becomes an illegal address prior to asynchronous I/O
completion, then the behavior is undefined.
If O_APPEND is not set for the file descriptor aio_fildes, then
the requested operation shall take place at the absolute position
in the file as given by aio_offset, as if lseek() were called
immediately prior to the operation with an offset equal to
aio_offset and a whence equal to SEEK_SET. If O_APPEND is set for
the file descriptor, or if aio_fildes is associated with a device
that is incapable of seeking, write operations append to the file
in the same order as the calls were made, except under
circumstances described in Section 2.8.2, Asynchronous I/O. After
a successful call to enqueue an asynchronous I/O operation, the
value of the file offset for the file is unspecified.
The aio_sigevent member specifies the notification which occurs
when the request is completed.
The aiocbp->aio_lio_opcode field shall be ignored by aio_write().
Simultaneous asynchronous operations using the same aiocbp produce
undefined results.
If synchronized I/O is enabled on the file associated with
aiocbp->aio_fildes, the behavior of this function shall be
according to the definitions of synchronized I/O data integrity
completion, and synchronized I/O file integrity completion.
For any system action that changes the process memory space while
an asynchronous I/O is outstanding to the address range being
changed, the result of that action is undefined.
For regular files, no data transfer shall occur past the offset
maximum established in the open file description associated with
aiocbp->aio_fildes.
The aio_write() function shall return the value zero if the I/O
operation is successfully queued; otherwise, the function shall
return the value -1 and set errno to indicate the error.
The aio_write() function shall fail if:
EAGAIN The requested asynchronous I/O operation was not queued due
to system resource limitations.
Each of the following conditions may be detected synchronously at
the time of the call to aio_write(), or asynchronously. If any of
the conditions below are detected synchronously, the aio_write()
function shall return -1 and set errno to the corresponding value.
If any of the conditions below are detected asynchronously, the
return status of the asynchronous operation shall be set to -1,
and the error status of the asynchronous operation is set to the
corresponding value.
EBADF The aiocbp->aio_fildes argument is not a valid file
descriptor open for writing.
EINVAL The file offset value implied by aiocbp->aio_offset would
be invalid,
aiocbp->aio_reqprio is not a valid value, or
aiocbp->aio_nbytes is an invalid value.
In the case that the aio_write() successfully queues the I/O
operation, the return status of the asynchronous operation shall
be one of the values normally returned by the write() function
call. If the operation is successfully queued but is subsequently
canceled or encounters an error, the error status for the
asynchronous operation contains one of the values normally set by
the write() function call, or one of the following:
EBADF The aiocbp->aio_fildes argument is not a valid file
descriptor open for writing.
EINVAL The file offset value implied by aiocbp->aio_offset would
be invalid.
ECANCELED
The requested I/O was canceled before the I/O completed due
to an explicit aio_cancel() request.
The following condition may be detected synchronously or
asynchronously:
EFBIG The file is a regular file, aiobcp->aio_nbytes is greater
than 0, and the starting offset in aiobcp->aio_offset is at
or beyond the offset maximum in the open file description
associated with aiocbp->aio_fildes.
The following sections are informative.
None.
None.
None.
None.
Section 2.8.2, Asynchronous I/O, aio_cancel(3p), aio_error(3p),
aio_read(3p), aio_return(3p), close(3p), exec(1p), exit(3p),
fork(3p), lio_listio(3p), lseek(3p), write(3p)
The Base Definitions volume of POSIX.1‐2017, aio.h(0p)
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics Engineers,
Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard,
the original IEEE and The Open Group Standard is the referee
document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of
the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 AIO_WRITE(3P)
Pages that refer to this page: aio.h(0p), aio_cancel(3p), aio_error(3p), aio_read(3p), aio_return(3p), aio_suspend(3p), lio_listio(3p)
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HTML rendering created 2025-02-02 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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