aio_group_completion_np(3) Library Functions Manual aio_group_completion_np(3)NAME
aio_group_completion_np - Enables the use of aio_results_np function
LIBRARY
Asynchronous I/O Library (libaio, libaio_raw)
SYNOPSIS
#include <aio.h>
int aio_group_completion_np ( void );
PARAMETERS
None.
DESCRIPTION
The aio_group_completion_np function enables an application to use aio group completion through the aio_result_np function.
The function must be called before any other aio function. After this call, the use of the aio_error and aio_return functions becomes
undefined, and they may return unexpected errors. The best practice is never to intermix the two forms of aio completion. Calling the
function after the use of any other aio function results in failure.
RETURN VALUES
If the function returns successfully, the number of completed aio operations reported on is returned. That is, the return value is the
number of valid entries 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_group_completion_np function fails under the following conditions:
[EINVAL] Another aio function has already been called.
[EAGAIN] Inadequate system resources exist to enable group completion at this time.
RELATED INFORMATION
Functions: aio_read(3), aio_results_np(3), aio_suspend(3), aio_write(3), lio_listio(3)
Guide to Realtime Programming delim off
aio_group_completion_np(3)
Check Out this Related Man Page
aio_results_np(3) Library Functions Manual aio_results_np(3)NAME
aio_results_np - Returns results for completed asynchronous I/O operations
LIBRARY
Asynchronous I/O Library (libaio, libaio_raw)
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 list[],
int nent,
const struct timespec *timeout,
int howmany);
PARAMETERS
list An array of pointers to asynchronous I/O completion data structures.
nent 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 completions not yet reported on.
timeout 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.
howmany 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 opera-
tions are completed, the call returns the requested results without suspending 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 operations reported on is returned. That is, the return value is the
number 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:
[EINTR] A signal interrupted the function.
[EINVAL] An invalid time value was specified in timeout.
[EINVAL] The nent parameter is negative.
[EINVAL] The list paramenter is null.
[EINVAL] The howmany parameter is greater than the nent parameter.
RELATED INFORMATION
Functions: aio_group_completion_np(3), aio_read(3), aio_suspend(3), aio_write(3), lio_listio(3)
Guide to Realtime Programming delim off
aio_results_np(3)