lio_listio(3)

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

6       lio_listio - initiate a list of I/O requests
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SYNOPSIS

9       #include <aio.h>
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11       int lio_listio(int mode, struct aiocb *const aiocb_list[],
12                      int nitems, struct sigevent *sevp);
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14       Link with -lrt.
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DESCRIPTION

17       The   lio_listio()  function  initiates  the  list  of  I/O  operations
18       described by the array aiocb_list.
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20       The mode operation has one of the following values:
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22       LIO_WAIT    The call blocks until all  operations  are  complete.   The
23                   sevp argument is ignored.
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25       LIO_NOWAIT  The  I/O  operations are queued for processing and the call
26                   returns immediately.  When all of the I/O  operations  com‐
27                   plete,  asynchronous  notification  occurs, as specified by
28                   the sevp argument; see sigevent(7) for details.  If sevp is
29                   NULL, no asynchronous notification occurs.
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31       The  aiocb_list  argument  is  an array of pointers to aiocb structures
32       that describe I/O operations.  These  operations  are  executed  in  an
33       unspecified order.  The nitems argument specifies the size of the array
34       aiocb_list.  null pointers in aiocb_list are ignored.
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36       In each control block in aiocb_list, the aio_lio_opcode field specifies
37       the I/O operation to be initiated, as follows:
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39       LIO_READ  Initiate  a read operation.  The operation is queued as for a
40                 call to aio_read(3) specifying this control block.
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42       LIO_WRITE Initiate a write operation.  The operation is queued as for a
43                 call to aio_write(3) specifying this control block.
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45       LIO_NOP   Ignore this control block.
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47       The  remaining  fields  in each control block have the same meanings as
48       for aio_read(3) and aio_write(3).  The aio_sigevent fields of each con‐
49       trol  block can be used to specify notifications for the individual I/O
50       operations (see sigevent(7)).
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RETURN VALUE

53       If mode is LIO_NOWAIT, lio_listio() returns 0 if all I/O operations are
54       successfully  queued.   Otherwise,  -1 is returned, and errno is set to
55       indicate the error.
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57       If mode is LIO_WAIT, lio_listio() returns 0 when all of the I/O  opera‐
58       tions  have  completed  successfully.   Otherwise,  -1 is returned, and
59       errno is set to indicate the error.
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61       The return status from lio_listio() provides information only about the
62       call  itself,  not about the individual I/O operations.  One or more of
63       the I/O operations may fail, but this does not prevent other operations
64       completing.   The status of individual I/O operations in aiocb_list can
65       be determined using aio_error(3).  When an operation has completed, its
66       return  status  can  be  obtained  using aio_return(3).  Individual I/O
67       operations can fail  for  the  reasons  described  in  aio_read(3)  and
68       aio_write(3).
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ERRORS

71       The lio_listio() function may fail for the following reasons:
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73       EAGAIN Out of resources.
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75       EAGAIN The number of I/O operations specified by nitems would cause the
76              limit AIO_MAX to be exceeded.
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78       EINTR  mode was LIO_WAIT and a signal was caught before all I/O  opera‐
79              tions  completed;  see  signal(7).  (This may even be one of the
80              signals used for asynchronous I/O completion notification.)
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82       EINVAL mode is invalid, or nitems exceeds the limit AIO_LISTIO_MAX.
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84       EIO    One of more of the operations specified  by  aiocb_list  failed.
85              The  application  can  check  the status of each operation using
86              aio_return(3).
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88       If lio_listio() fails with the error EAGAIN, EINTR, or EIO,  then  some
89       of  the  operations in aiocb_list may have been initiated.  If lio_lis‐
90       tio() fails for any other reason, then none of the I/O  operations  has
91       been initiated.
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VERSIONS

94       The lio_listio() function is available since glibc 2.1.
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ATTRIBUTES

97       For   an   explanation   of   the  terms  used  in  this  section,  see
98       attributes(7).
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100       ┌─────────────┬───────────────┬─────────┐
101       │Interface    │ Attribute     │ Value   │
102       ├─────────────┼───────────────┼─────────┤
103       │lio_listio() │ Thread safety │ MT-Safe │
104       └─────────────┴───────────────┴─────────┘
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CONFORMING TO

107       POSIX.1-2001, POSIX.1-2008.
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NOTES

110       It is a good idea to zero out the control blocks before use.  The  con‐
111       trol  blocks  must  not  be  changed  while  the  I/O operations are in
112       progress.  The buffer areas being read into or written from must not be
113       accessed  during  the  operations  or undefined results may occur.  The
114       memory areas involved must remain valid.
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116       Simultaneous I/O operations specifying the same aiocb structure produce
117       undefined results.
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COLOPHON

124       This page is part of release 4.16 of the Linux  man-pages  project.   A
125       description  of  the project, information about reporting bugs, and the
126       latest    version    of    this    page,    can     be     found     at
127       https://www.kernel.org/doc/man-pages/.
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131                                  2017-09-15                     LIO_LISTIO(3)