man3/aio_suspend.3

   1 '\" t
   2 .\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl)
   3 .\" and Copyright (C) 2010 Michael Kerrisk <mtk.manpages@gmail.com>
   4 .\"
   5 .\" SPDX-License-Identifier: GPL-2.0-or-later
   6 .\"
   7 .TH aio_suspend 3 (date) "Linux man-pages (unreleased)"
   8 .SH NAME
   9 aio_suspend \- wait for asynchronous I/O operation or timeout
  10 .SH LIBRARY
  11 Real-time library
  12 .RI ( librt ", " \-lrt )
  13 .SH SYNOPSIS
  14 .nf
  15 .PP
  16 .B "#include <aio.h>"
  17 .PP
  18 .BI "int aio_suspend(const struct aiocb *const " aiocb_list "[], int " nitems ,
  19 .BI "                const struct timespec *restrict " timeout );
  20 .fi
  21 .SH DESCRIPTION
  22 The
  23 .BR aio_suspend ()
  24 function suspends the calling thread until one of the following occurs:
  25 .IP \(bu 3
  26 One or more of the asynchronous I/O requests in the list
  27 .I aiocb_list
  28 has completed.
  29 .IP \(bu
  30 A signal is delivered.
  31 .IP \(bu
  32 .I timeout
  33 is not NULL and the specified time interval has passed.
  34 (For details of the
  35 .I timespec
  36 structure, see
  37 .BR nanosleep (2).)
  38 .PP
  39 The
  40 .I nitems
  41 argument specifies the number of items in
  42 .IR aiocb_list .
  43 Each item in the list pointed to by
  44 .I aiocb_list
  45 must be either NULL (and then is ignored),
  46 or a pointer to a control block on which I/O was initiated using
  47 .BR aio_read (3),
  48 .BR aio_write (3),
  49 or
  50 .BR lio_listio (3).
  51 (See
  52 .BR aio (7)
  53 for a description of the
  54 .I aiocb
  55 structure.)
  56 .PP
  57 If
  58 .B CLOCK_MONOTONIC
  59 is supported, this clock is used to measure
  60 the timeout interval (see
  61 .BR clock_gettime (2)).
  62 .SH RETURN VALUE
  63 If this function returns after completion of one of the I/O
  64 requests specified in
  65 .IR aiocb_list ,
  66 0 is returned.
  67 Otherwise, \-1 is returned, and
  68 .I errno
  69 is set to indicate the error.
  70 .SH ERRORS
  71 .TP
  72 .B EAGAIN
  73 The call timed out before any of the indicated operations
  74 had completed.
  75 .TP
  76 .B EINTR
  77 The call was ended by signal
  78 (possibly the completion signal of one of the operations we were
  79 waiting for); see
  80 .BR signal (7).
  81 .TP
  82 .B ENOSYS
  83 .BR aio_suspend ()
  84 is not implemented.
  85 .SH VERSIONS
  86 The
  87 .BR aio_suspend ()
  88 function is available since glibc 2.1.
  89 .SH ATTRIBUTES
  90 For an explanation of the terms used in this section, see
  91 .BR attributes (7).
  92 .ad l
  93 .nh
  94 .TS
  95 allbox;
  96 lbx lb lb
  97 l l l.
  98 Interface       Attribute       Value
  99 T{
 100 .BR aio_suspend ()
 101 T}      Thread safety   MT-Safe
 102 .TE
 103 .hy
 104 .ad
 105 .sp 1
 106 .SH STANDARDS
 107 POSIX.1-2001, POSIX.1-2008.
 108 .PP
 109 POSIX doesn't specify the parameters to be
 110 .IR restrict ;
 111 that is specific to glibc.
 112 .SH NOTES
 113 One can achieve polling by using a non-NULL
 114 .I timeout
 115 that specifies a zero time interval.
 116 .PP
 117 If one or more of the asynchronous I/O operations specified in
 118 .I aiocb_list
 119 has already completed at the time of the call to
 120 .BR aio_suspend (),
 121 then the call returns immediately.
 122 .PP
 123 To determine which I/O operations have completed
 124 after a successful return from
 125 .BR aio_suspend (),
 126 use
 127 .BR aio_error (3)
 128 to scan the list of
 129 .I aiocb
 130 structures pointed to by
 131 .IR aiocb_list .
 132 .SH BUGS
 133 The glibc implementation of
 134 .BR aio_suspend ()
 135 is not async-signal-safe,
 136 .\" FIXME . https://sourceware.org/bugzilla/show_bug.cgi?id=13172
 137 in violation of the requirements of POSIX.1.
 138 .SH SEE ALSO
 139 .BR aio_cancel (3),
 140 .BR aio_error (3),
 141 .BR aio_fsync (3),
 142 .BR aio_read (3),
 143 .BR aio_return (3),
 144 .BR aio_write (3),
 145 .BR lio_listio (3),
 146 .BR aio (7),
 147 .BR time (7)