* poll.cc: New file. Implement `poll' system call.

* include/poll.h: Ditto.
        * include/sys/poll.h: Ditto.
        * Makefile.in: Add poll.o as dependency.
        * cygwin.din: Add poll and _poll symbols.

winsup/cygwin/poll.cc

@@ -0,0 +1,63 @@
+/* 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 <sys/poll.h>
+#include "winsup.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 (&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;
+}