74 lines
2.4 KiB
C++
74 lines
2.4 KiB
C++
![]() |
/*******************************************************************************
|
||
|
|
||
|
Copyright(C) Jonas 'Sortie' Termansen 2013.
|
||
|
|
||
|
This file is part of the Sortix C Library.
|
||
|
|
||
|
The Sortix C Library is free software: you can redistribute it and/or modify
|
||
|
it under the terms of the GNU Lesser General Public License as published by
|
||
|
the Free Software Foundation, either version 3 of the License, or (at your
|
||
|
option) any later version.
|
||
|
|
||
|
The Sortix C Library is distributed in the hope that it will be useful, but
|
||
|
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|
||
|
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
|
||
|
License for more details.
|
||
|
|
||
|
You should have received a copy of the GNU Lesser General Public License
|
||
|
along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
|
||
|
|
||
|
select.cpp
|
||
|
Waiting on multiple file descriptors.
|
||
|
|
||
|
*******************************************************************************/
|
||
|
|
||
|
#include <sys/select.h>
|
||
|
|
||
|
#include <poll.h>
|
||
|
|
||
|
extern "C"
|
||
|
int select(int nfds, fd_set* restrict readfds, fd_set* restrict writefds,
|
||
|
fd_set* restrict exceptfds, struct timeval* restrict timeout)
|
||
|
{
|
||
|
const int READ_EVENTS = POLLIN | POLLRDNORM;
|
||
|
const int WRITE_EVENTS = POLLOUT | POLLWRNORM;
|
||
|
const int EXCEPT_EVENTS = POLLERR | POLLHUP;
|
||
|
struct pollfd fds[FD_SETSIZE];
|
||
|
for ( int i = 0; i < nfds; i++ )
|
||
|
{
|
||
|
fds[i].fd = i;
|
||
|
fds[i].events = fds[i].revents = 0;
|
||
|
if ( FD_ISSET(i, readfds) )
|
||
|
fds[i].events |= READ_EVENTS;
|
||
|
if ( FD_ISSET(i, writefds) )
|
||
|
fds[i].events |= WRITE_EVENTS;
|
||
|
if ( FD_ISSET(i, exceptfds) )
|
||
|
fds[i].events |= EXCEPT_EVENTS;
|
||
|
if ( !fds[i].events )
|
||
|
fds[i].fd = -1;
|
||
|
}
|
||
|
struct timespec* timeout_tsp = NULL;
|
||
|
struct timespec timeout_ts;
|
||
|
if ( timeout )
|
||
|
timeout_tsp = &timeout_ts,
|
||
|
timeout_tsp->tv_sec = timeout->tv_sec,
|
||
|
timeout_tsp->tv_nsec = (long) timeout->tv_usec * 1000;
|
||
|
int num_occur = ppoll(fds, nfds, timeout_tsp, NULL);
|
||
|
if ( num_occur < 0 )
|
||
|
return -1;
|
||
|
if ( readfds ) FD_ZERO(readfds);
|
||
|
if ( writefds ) FD_ZERO(writefds);
|
||
|
if ( exceptfds ) FD_ZERO(exceptfds);
|
||
|
int ret = 0;
|
||
|
for ( int i = 0; i < nfds; i++ )
|
||
|
{
|
||
|
if ( !fds[i].events )
|
||
|
continue;
|
||
|
int events = fds[i].revents;
|
||
|
if ( events & READ_EVENTS && readfds ) { FD_SET(i, readfds); ret++; }
|
||
|
if ( events & WRITE_EVENTS && writefds ) { FD_SET(i, writefds); ret++; }
|
||
|
if ( events & EXCEPT_EVENTS && exceptfds ) { FD_SET(i, exceptfds); ret++; }
|
||
|
}
|
||
|
return ret;
|
||
|
}
|