newlib-cygwin/winsup/cygwin/poll.cc

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/* poll.cc. Implements poll(2) via usage of select(2) call.
Copyright 2000 Cygnus Solutions.
This file is part of Cygwin.
This software is a copyrighted work licensed under the terms of the
Cygwin license. Please consult the file "CYGWIN_LICENSE" for
details. */
#include "winsup.h"
#include <sys/poll.h>
extern "C"
int
poll (struct pollfd *fds, unsigned int nfds, int timeout)
{
int max_fd = 0;
fd_set open_fds, read_fds, write_fds, except_fds;
struct timeval tv = { timeout / 1000, (timeout % 1000) * 1000 };
FD_ZERO (&open_fds);
FD_ZERO (&read_fds);
FD_ZERO (&write_fds);
FD_ZERO (&except_fds);
for (unsigned int i = 0; i < nfds; ++i)
if (!dtable.not_open (fds[i].fd))
{
FD_SET (fds[i].fd, &open_fds);
if (fds[i].events & POLLIN)
FD_SET (fds[i].fd, &read_fds);
if (fds[i].events & POLLOUT)
FD_SET (fds[i].fd, &write_fds);
if (fds[i].events & POLLPRI)
FD_SET (fds[i].fd, &except_fds);
if (fds[i].fd > max_fd)
max_fd = fds[i].fd;
}
int ret = cygwin_select (max_fd + 1, &read_fds, &write_fds, &except_fds,
timeout < 0 ? NULL : &tv);
if (ret >= 0)
for (unsigned int i = 0; i < nfds; ++i)
{
if (!FD_ISSET (fds[i].fd, &open_fds))
fds[i].revents = POLLNVAL;
else if (dtable.not_open(fds[i].fd))
fds[i].revents = POLLHUP;
else
{
fds[i].revents = 0;
if (FD_ISSET (fds[i].fd, &read_fds))
fds[i].revents |= POLLIN;
if (FD_ISSET (fds[i].fd, &write_fds))
fds[i].revents |= POLLOUT;
if (FD_ISSET (fds[i].fd, &except_fds))
fds[i].revents |= POLLPRI;
}
}
return ret;
}