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)