iob_write(3) [debian man page]

iob_write(3)						     Library Functions Manual						      iob_write(3)

NAME

       iob_write - send I/O batch through callback

SYNTAX

       #include <iob.h>

       typedef int64 (*io_write_callback)(int64 s,const void* buf,uint64 n);

       int64 iob_write(int64 s,io_batch* b,io_write_callback cb);

DESCRIPTION

       iob_write sends the (rest of) b through the callback cb, passing s as first argument.  cb is expected to behave like io_trywrite(2).

       This  interface	is intended to send an I/O batch through a filter, for example to encrypt or compress it.  If you just want to send an I/O
       batch to a socket, use iob_send instead.

       iob_write 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_write 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.

NOTE

       iob_write will continue to call your callback until it returns an error.  So if you are in a state machine, for example a web server  using
       this  for  SSL  support,  make  sure  to  write at most n bytes at a time (e.g. 64k) and the next time you are called return -1.  Otherwise
       iob_write might not return until the whole file is served.

SEE ALSO

       iob_send(3)

																      iob_write(3)

io_tryread(3)						     Library Functions Manual						     io_tryread(3)

NAME

       io_tryread - read from a descriptor without blocking

SYNTAX

       #include <io.h>

       int io_tryread(int64 fd,char* buf,int64 len);

DESCRIPTION

       io_tryread  tries to read len bytes of data from descriptor fd into buf[0], buf[1], ..., buf[len-1]. (The effects are undefined if len is 0
       or smaller.) There are several possible results:

       o  o_tryread returns an integer between 1 and len: This number of bytes was available for immediate reading; the bytes were read  into  the
	  beginning  of  buf. Note that this number can be, and often is, smaller than len; you must not assume that io_tryread always succeeds in
	  reading exactly len bytes.

       o  io_tryread returns 0: No bytes were read, because the descriptor is at end of file. For example, this descriptor has reached the end	of
	  a disk file, or is reading an empty pipe that has been closed by all writers.

       o  io_tryread  returns -1, setting errno to EAGAIN: No bytes were read, because the descriptor is not ready. For example, the descriptor is
	  reading an empty pipe that could still be written to.

       o  io_tryread returns -3, setting errno to something other than EAGAIN: No bytes were read, because the read attempt encountered a  persis-
	  tent error, such as a serious disk failure (EIO), an unreachable network (ENETUNREACH), or an invalid descriptor number (EBADF).

       io_tryread does not pause waiting for a descriptor that is not ready.  If you want to pause, use io_waitread or io_wait.

       You can make io_tryread faster and more efficient by making the socket non-blocking with io_nonblock().

SEE ALSO

       io_nonblock(3), io_waitread(3), io_tryreadtimeout(3)

																     io_tryread(3)