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 outstanding 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)

COLOPHON
       This page is part of release 3.74 of the Linux man-pages project.  A  description  of  the
       project,  information  about  reporting  bugs, and the latest version of this page, can be
       found at http://www.kernel.org/doc/man-pages/.



Linux                                       2012-04-26                                AIO_INIT(3)