NAME

       io_canread - return a file descriptor that can be read from

SYNTAX

       #include <io.h>

       int64 io_canread();

DESCRIPTION

       io_canread  returns the next file descriptor that can be read from.  You have to have used
       io_wantread() on the file descriptor earlier, and you have to  have  called  io_wait()  or
       io_waituntil().

       These  functions  then  keep an internal data structure on which descriptors were reported
       readable by the operating system.

       Please note that there is no guarantee that there still is data that can be read from  the
       descriptor,  just  that  there  was  data  when  io_wait()  or io_waituntil() were called.
       Another  process  could  have  read  the  data  before  you.   Look  at  the  result  from
       io_tryread().

       If  there are no more descriptors that you can write to without blocking, io_canwrite will
       return -1.  In this case you should call io_wait() or io_waituntil() again.

       You should use io_tryread(3) to read from the descriptor, not plain read(2).  If  you  use
       read(2) and you get EAGAIN, call io_eagain(3).

SEE ALSO

       io_wait(3), io_canwrite(3), io_eagain(3)

                                                                                    io_canread(3)