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

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