1io_canwrite(3)             Library Functions Manual             io_canwrite(3)
2
3
4

NAME

6       io_canwrite - return a file descriptor that can be written to
7

SYNTAX

9       #include <io.h>
10
11       int64 io_canwrite();
12

DESCRIPTION

14       io_canwrite  returns  the  next file descriptor that can be written to.
15       You have to have used io_wantwrite() on the  file  descriptor  earlier,
16       and you have to have called io_wait() or io_waituntil().
17
18       These  functions then keep an internal data structure on which descrip‐
19       tors were reported writable by the operating system.
20
21       Please note that there is no guarantee that you can  still  write  data
22       without blocking to that descriptor, just that you could when io_wait()
23       or io_waituntil() were called.   Another  process  could  have  written
24       something before you.  Look at the result from io_trywrite().
25
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.
29
30       You  should  only  use io_trywrite(3), io_sendfile(3) or iob_send(3) to
31       write to the file, not plain write(2).  If you  use  write(2)  and  get
32       EAGAIN, call io_eagain(3).
33

SEE ALSO

35       io_wait(3), io_canwrite(3)
36
37
38
39                                                                io_canwrite(3)
Impressum