aio_init(3) — Linux manual page


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

NAME         top

       aio_init - asynchronous I/O initialization

SYNOPSIS         top

       #define _GNU_SOURCE         /* See feature_test_macros(7) */
       #include <aio.h>

       void aio_init(const struct aioinit *init);

       Link with -lrt.

DESCRIPTION         top

       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:

              This field specifies the maximum number of worker threads that
              may be used by the implementation.  If the number of outstand‐
              ing 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.

              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.

              This field specifies the amount of time in seconds that a
              worker thread should wait for further requests before termi‐
              nating, after having completed a previous request.  The
              default value is 1.

VERSIONS         top

       The aio_init() function is available since glibc 2.1.

CONFORMING TO         top

       This function is a GNU extension.

SEE ALSO         top


COLOPHON         top

       This page is part of release 5.08 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

Linux                            2020-08-13                      AIO_INIT(3)

Pages that refer to this page: aio(7)