io_wait(3) [debian man page]

io_wait(3)						     Library Functions Manual							io_wait(3)

NAME

       io_wait - wait for events

SYNTAX

       #include <io.h>

       void io_wait();

DESCRIPTION

       io_wait()  checks  the  descriptors  that  the  program	is  interested in to see whether any of them are ready. If none of them are ready,
       io_wait() tries to pause until one of them is ready, so that it does not take time away from other programs running on the same computer.

       io_wait pays attention to timeouts: if a descriptor reaches its timeout, and the program is interested in reading or writing that  descrip-
       tor, io_wait will return promptly.

       Under  some  circumstances,  io_wait will return even though no interesting descriptors are ready. Do not assume that a descriptor is ready
       merely because io_wait has returned.

       io_wait is not interrupted by the delivery of a signal. Programs that expect interruption are unreliable: they will block if the same  sig-
       nal is delivered a moment before io_wait. The correct way to handle signals is with the self-pipe trick.

SEE ALSO

       io_waituntil(3), io_check(3), io_wantread(3), io_wantwrite(3), io_fd(3)

																	io_wait(3)

io_canwrite(3)						     Library Functions Manual						    io_canwrite(3)

NAME

       io_canwrite - return a file descriptor that can be written to

SYNTAX

       #include <io.h>

       int64 io_canwrite();

DESCRIPTION

       io_canwrite  returns the next file descriptor that can be written to.  You have to have used io_wantwrite() 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 writable by the operating system.

       Please note that there is no guarantee that you can still write data without  blocking  to  that  descriptor,  just  that  you  could  when
       io_wait() or io_waituntil() were called.  Another process could have written something before you.  Look at the result from io_trywrite().

       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 only use io_trywrite(3), io_sendfile(3) or iob_send(3) to write to the file, not plain write(2).  If you use	write(2)  and  get
       EAGAIN, call io_eagain(3).

SEE ALSO

       io_wait(3), io_canwrite(3)

																    io_canwrite(3)