io_canread(3) [debian man page]

io_canread(3)						     Library Functions Manual						     io_canread(3)

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)

iob_send(3)						     Library Functions Manual						       iob_send(3)

NAME

       iob_send - send I/O batch

SYNTAX

       #include <iob.h>

       int64 iob_send(int64 s,io_batch* b);

DESCRIPTION

       iob_send sends the (rest of) b over the socket s.

       iob_send  returns  the number of bytes written, 0 if there were no more bytes to be written in the batch, -1 for EAGAIN, or -3 for a perma-
       nent error (for example "connection reset by peer").

       The normal usage pattern is using io_wait to know when a descriptor is writable, and then calling iob_send until it returns 0, -1 or -3.

       If it returns 0, terminate the loop (everything was written OK).  If it returns -1, call io_wait again.	If it returned -3, signal an error
       and close the socket.

       The benefit of the I/O batch API is that it exploits platform specific APIs like FreeBSD's sendfile.  The file contents will always be sent
       in a way that allows the operating systems to perform zero copy TCP, and the buffers will always be sent using as few syscalls as  possible
       and avoiding unnecessary copying (using writev).

SEE ALSO

       iob_reset(3), iob_send(3), iob_addbuf(3), iob_adds_free(3), iob_addfile(3), iob_prefetch(3)

																       iob_send(3)