AIO_INIT(3) Linux Programmer's Manual AIO_INIT(3)NAME
aio_init - asynchronous I/O initialization
SYNOPSIS
#define _GNU_SOURCE /* See feature_test_macros(7) */
#include <aio.h>
void aio_init(const struct aioinit *init);
Link with -lrt.
DESCRIPTION
The GNU-specific aio_init() function allows the caller to provide tuning hints to the glibc POSIX AIO implementation. Use of this function
is optional, but to be effective, it must be called before employing any other functions in the POSIX AIO API.
The tuning information is provided in the buffer pointed to by the argument init. This buffer is a structure of the following form:
struct aioinit {
int aio_threads; /* Maximum number of threads */
int aio_num; /* Number of expected simultaneous
requests */
int aio_locks; /* Not used */
int aio_usedba; /* Not used */
int aio_debug; /* Not used */
int aio_numusers; /* Not used */
int aio_idle_time; /* Number of seconds before idle thread
terminates (since glibc 2.2) */
int aio_reserved;
};
The following fields are used in the aioinit structure:
aio_threads This field specifies the maximum number of worker threads that may be used by the implementation. If the number of out-
standing I/O operations exceeds this limit, then excess operations will be queued until a worker thread becomes free. If
this field is specified with a value less than 1, the value 1 is used. The default value is 20.
aio_num This field should specify the maximum number of simultaneous I/O requests that the caller expects to enqueue. If a value
less than 32 is specified for this field, it is rounded up to 32. The default value is 64.
aio_idle_time This field specifies the amount of time in seconds that a worker thread should wait for further requests before terminating,
after having completed a previous request. The default value is 1.
VERSIONS
The aio_init() function is available since glibc 2.1.
CONFORMING TO
This function is a GNU extension.
SEE ALSO aio(7)Linux 2012-04-26 AIO_INIT(3)
Check Out this Related Man Page
AIO_SUSPEND(3) Linux Programmer's Manual AIO_SUSPEND(3)NAME
aio_suspend - wait for asynchronous I/O operation or timeout
SYNOPSIS
#include <aio.h>
int aio_suspend(const struct aiocb * const aiocb_list[],
int nitems, const struct timespec *timeout);
Link with -lrt.
DESCRIPTION
The aio_suspend() function suspends the calling thread until one of the following occurs:
* One or more of the asynchronous I/O requests in the list aiocb_list has completed.
* A signal is delivered.
* timeout is not NULL and the specified time interval has passed. (For details of the timespec structure, see nanosleep(2).)
The nitems argument specifies the number of items in aiocb_list. Each item in the list pointed to by aiocb_list must be either NULL (and
then is ignored), or a pointer to a control block on which I/O was initiated using aio_read(3), aio_write(3), or lio_listio(3). (See
aio(7) for a description of the aiocb structure.)
If CLOCK_MONOTONIC is supported, this clock is used to measure the timeout interval (see clock_gettime(3)).
RETURN VALUE
If this function returns after completion of one of the I/O requests specified in aiocb_list, 0 is returned. Otherwise, -1 is returned,
and errno is set to indicate the error.
ERRORS
EAGAIN The call timed out before any of the indicated operations had completed.
EINTR The call was ended by signal (possibly the completion signal of one of the operations we were waiting for); see signal(7).
ENOSYS aio_suspend() is not implemented.
VERSIONS
The aio_suspend() function is available since glibc 2.1.
CONFORMING TO
POSIX.1-2001, POSIX.1-2008.
NOTES
One can achieve polling by using a non-NULL timeout that specifies a zero time interval.
If one or more of the asynchronous I/O operations specified in aiocb_list has already completed at the time of the call to aio_suspend(),
then the call returns immediately.
To determine which I/O operations have completed after a successful return from aio_suspend(), use aio_error(3) to scan the list of aiocb
structures pointed to by aiocb_list.
SEE ALSO aio_cancel(3), aio_error(3), aio_fsync(3), aio_read(3), aio_return(3), aio_write(3), lio_listio(3), aio(7), time(7)COLOPHON
This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
2012-05-08 AIO_SUSPEND(3)