Section: Linux Programmer's Manual (3)
aio_read - asynchronous read
int aio_read(struct aiocb *aiocbp);
Link with -lrt.
function queues the I/O request described by the buffer pointed to by
This function is the asynchronous analog of
The arguments of the call
read(fd, buf, count)
correspond (in order) to the fields
of the structure pointed to by
for a description of the
The data is read starting at the absolute position
regardless of the file offset.
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 read may or may not have completed
when the call returns.
One tests for completion using
The return status of a completed I/O operation can be obtained by
Asynchronous notification of I/O completion can be obtained by setting
is defined, and this file supports it,
then the asynchronous operation is submitted at a priority equal
to that of the calling process minus
No data is read from a regular file beyond its maximum offset.
On success, 0 is returned.
On error, the request is not enqueued, -1
is returned, and
is set appropriately.
If an error is detected only later, it will
be reported via
(returns status -1) and
(error status---whatever one would have gotten in
Out of resources.
is not a valid file descriptor open for reading.
One or more of
is not implemented.
The file is a regular file, we start reading before end-of-file
and want at least one byte, but the starting position is past
the maximum offset for this file.
function is available since glibc 2.1.
For an explanation of the terms used in this section, see
It is a good idea to zero out the control block before use.
The control block must not be changed while the read operation
is in progress.
The buffer area being read into
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
structure produce undefined results.
This page is part of release 5.07 of the Linux
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at