aio_results_np(3)aio_results_np(3)NAMEaio_results_np - Returns results for completed asynchronous I/O opera‐
tions
SYNOPSIS
#include <aio.h>
typedef struct aio_completion_data {
struct aiocb *aio_aiocb;
ssize_t aio_result;
int aio_error;
aio_completion_t;int aio_results_np( aio_completion_t
listchoice="opt">, int nent, const struct timespec *timeout, int how‐
many);
LIBRARY
Asynchronous I/O Library (libaio, libaio_raw)
PARAMETERS
An array of pointers to asynchronous I/O completion data structures.
The number of elements in the array. This number specifies the number
of completed asynchronous I/O operations that can be reported on. If
nent is 0 (zero), the function simply returns the number of aio comple‐
tions not yet reported on. A pointer to a timespec structure. If
timeout is NULL, the argument is ignored. If howmany aio operations are
not completed within the timeout value, the function fails. The number
of aio operations that must be complete before the the call returns.
DESCRIPTION
The aio_results_np function suspends the calling process until at least
howmany asynchronous I/O operations have completed, until a signal
interrupts the function, or until a timeout interval, if specified, has
passed. If at the time of the call howmany asynchronous I/O operations
are completed, the call returns the requested results without suspend‐
ing the calling process.
The list argument is an array of pointers to aio_completion_t data
structures. The nent argument indicates the number of elements in the
array. On return from a successful call, the function return value
specifies the number of valid entries returned in the array. For each
valid entry, three pieces of information are returned: The aio_aiocb
field contains a pointer to a completed aiocb structure. The
aio_result field contains the return value of the operation; this value
is equivalent to the result of a call to aio_return for the aio_aiocb
field. The aio_error field contains the errno value of the operation;
this value is equivalent to the result of a call to aio_error for the
aio_aiocb field.
Each valid completion structure represents a completed aio operation.
The function performs the equivalent of an aio_return on each aiocb on
which it reports. In other words, the aiocb pointers returned are
ready for immediate reuse by the application.
If nent is 0 (zero), the function immediately returns the number of aio
completions not yet reported on. This can be used to quickly poll for
completion.
RETURN VALUES
If the function returns successfully, the number of completed aio oper‐
ations reported on is returned. That is, the return value is the num‐
ber of valid entries in in the array. If the value returned is the
same as the nent argument, more aio operations may be complete and can
be reported on by another call to aio_results_np.
On an unsuccessful call, a value of -1 is returned and errno is set to
indicate that an error occurred.
ERRORS
The aio_results_np function fails under the following conditions: A
signal interrupted the function. An invalid time value was specified
in timeout. The nent parameter is negative. The list paramenter is
null. The howmany parameter is greater than the nent parameter.
SEE ALSO
Functions: aio_group_completion_np(3), aio_read(3), aio_suspend(3),
aio_write(3), lio_listio(3)
Guide to Realtime Programming
aio_results_np(3)