1AIO_INIT(3)                Linux Programmer's Manual               AIO_INIT(3)
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NAME

6       aio_init - asynchronous I/O initialization
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SYNOPSIS

9       #define _GNU_SOURCE         /* See feature_test_macros(7) */
10       #include <aio.h>
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12       void aio_init(const struct aioinit *init);
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14       Link with -lrt.
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DESCRIPTION

17       The  GNU-specific aio_init() function allows the caller to provide tun‐
18       ing hints to the glibc POSIX AIO implementation.  Use of this  function
19       is  optional,  but  to be effective, it must be called before employing
20       any other functions in the POSIX AIO API.
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22       The tuning information is provided in the  buffer  pointed  to  by  the
23       argument init.  This buffer is a structure of the following form:
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25           struct aioinit {
26               int aio_threads;    /* Maximum number of threads */
27               int aio_num;        /* Number of expected simultaneous
28                                      requests */
29               int aio_locks;      /* Not used */
30               int aio_usedba;     /* Not used */
31               int aio_debug;      /* Not used */
32               int aio_numusers;   /* Not used */
33               int aio_idle_time;  /* Number of seconds before idle thread
34                                      terminates (since glibc 2.2) */
35               int aio_reserved;
36           };
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38       The following fields are used in the aioinit structure:
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40       aio_threads    This  field  specifies  the  maximum  number  of  worker
41                      threads that may be used by the implementation.  If  the
42                      number of outstanding I/O operations exceeds this limit,
43                      then excess operations will be  queued  until  a  worker
44                      thread  becomes free.  If this field is specified with a
45                      value less than 1, the value 1  is  used.   The  default
46                      value is 20.
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48       aio_num        This field should specify the maximum number of simulta‐
49                      neous I/O requests that the caller expects  to  enqueue.
50                      If  a value less than 32 is specified for this field, it
51                      is rounded up to 32.  The default value is 64.
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53       aio_idle_time  This field specifies the amount of time in seconds  that
54                      a  worker thread should wait for further requests before
55                      terminating, after having completed a previous  request.
56                      The default value is 1.
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VERSIONS

59       The aio_init() function is available since glibc 2.1.
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CONFORMING TO

62       This function is a GNU extension.
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SEE ALSO

65       aio(7)
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COLOPHON

68       This  page  is  part of release 4.16 of the Linux man-pages project.  A
69       description of the project, information about reporting bugs,  and  the
70       latest     version     of     this    page,    can    be    found    at
71       https://www.kernel.org/doc/man-pages/.
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75Linux                             2017-09-15                       AIO_INIT(3)