1io_canread(3)              Library Functions Manual              io_canread(3)
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NAME

6       io_canread - return a file descriptor that can be read from
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SYNTAX

9       #include <io.h>
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11       int64 io_canread();
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DESCRIPTION

14       io_canread returns the next file descriptor that can be read from.  You
15       have to have used io_wantread() on the file descriptor earlier, and you
16       have to have called io_wait() or io_waituntil().
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18       These  functions then keep an internal data structure on which descrip‐
19       tors were reported readable by the operating system.
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21       Please note that there is no guarantee that there still  is  data  that
22       can  be  read  from  the  descriptor,  just  that  there  was data when
23       io_wait() or io_waituntil() were called.  Another  process  could  have
24       read the data before you.  Look at the result from io_tryread().
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26       If  there  are no more descriptors that you can write to without block‐
27       ing, io_canwrite  will  return  -1.   In  this  case  you  should  call
28       io_wait() or io_waituntil() again.
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30       You  should  use  io_tryread(3)  to read from the descriptor, not plain
31       read(2).  If you use read(2) and you get EAGAIN, call io_eagain(3).
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SEE ALSO

34       io_wait(3), io_canwrite(3), io_eagain(3)
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38                                                                 io_canread(3)