iob_write(3)iob_write(3)NAMEiob_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);
DESCRIPTIONiob_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 permanent
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.
NOTEiob_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 ALSOiob_send(3)iob_write(3)
