add (ice-9 poll), a poll wrapper

[bpt/guile.git] / libguile / poll.c

diff --git a/libguile/poll.c b/libguile/poll.c
new file mode 100644 (file)
index 0000000..0304448
--- /dev/null
+++ b/libguile/poll.c
@@ -0,0 +1,146 @@
+/* Copyright (C) 2010 Free Software Foundation, Inc.
+ * 
+ * This 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.
+ *
+ * This 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 this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+
+\f
+
+#define _GNU_SOURCE
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include "libguile/_scm.h"
+#include "libguile/bytevectors.h"
+#include "libguile/numbers.h"
+#include "libguile/error.h"
+#include "libguile/validate.h"
+
+#include "libguile/poll.h"
+
+\f
+#ifdef HAVE_POLL_H
+#include <poll.h>
+#endif
+
+\f
+
+/* {Poll}
+ */
+
+/* Poll a set of file descriptors, waiting until one or more of them is
+   ready to perform input or output.
+
+   This is a low-level interface.  See the `(ice-9 poll)' module for a more
+   usable wrapper.
+
+   `pollfds' is expected to be a bytevector, laid out in contiguous blocks of 64
+   bits.  Each block has the format of one `struct pollfd': a 32-bit int file
+   descriptor, a 16-bit int events mask, and a 16-bit int revents mask.
+
+   The number of pollfd structures in `pollfds' is specified in
+   `nfds'. `pollfds' must be at least long enough to support that number of
+   structures. It may be longer, in which case the trailing entries are left
+   untouched.
+
+   The pollfds bytevector is modified directly, setting the returned events in
+   the final two bytes (the revents member).
+
+   If timeout is given and is non-negative, the poll will return after that
+   number of milliseconds if no fd became active.
+   */
+#ifdef HAVE_POLL
+static SCM
+scm_primitive_poll (SCM pollfds, SCM nfds, SCM timeout)
+#define FUNC_NAME "primitive-poll"
+{
+  int rv;
+  nfds_t c_nfds;
+  int c_timeout;
+  struct pollfd *fds;
+
+  SCM_VALIDATE_BYTEVECTOR (SCM_ARG1, pollfds);
+  c_nfds = scm_to_uint32 (nfds);
+  c_timeout = scm_to_int (timeout);
+  
+  if (SCM_UNLIKELY (SCM_BYTEVECTOR_LENGTH (pollfds)
+                    < c_nfds * sizeof(struct pollfd)))
+    SCM_OUT_OF_RANGE (SCM_ARG1, nfds);
+  
+  fds = (struct pollfd*)SCM_BYTEVECTOR_CONTENTS (pollfds);
+  
+  SCM_SYSCALL (rv = poll (fds, c_nfds, c_timeout));
+
+  if (rv == -1)
+    SCM_SYSERROR;
+
+  return scm_from_int (rv);
+}
+#undef FUNC_NAME
+#endif /* HAVE_POLL */
+
+
+\f
+
+static void
+scm_init_poll (void)
+{
+#if HAVE_POLL
+  scm_c_define_gsubr ("primitive-poll", 3, 0, 0, scm_primitive_poll);
+#else
+  scm_misc_error ("%init-poll", "`poll' unavailable on this platform", SCM_EOL);
+#endif
+
+#ifdef POLLIN
+  scm_c_define ("POLLIN", scm_from_int (POLLIN));
+#endif                
+#ifdef POLLPRI
+  scm_c_define ("POLLPRI", scm_from_int (POLLPRI));
+#endif                
+#ifdef POLLOUT
+  scm_c_define ("POLLOUT", scm_from_int (POLLOUT));
+#endif                
+#ifdef POLLRDHUP
+  scm_c_define ("POLLRDHUP", scm_from_int (POLLRDHUP));
+#endif                
+#ifdef POLLERR
+  scm_c_define ("POLLERR", scm_from_int (POLLERR));
+#endif                
+#ifdef POLLHUP
+  scm_c_define ("POLLHUP", scm_from_int (POLLHUP));
+#endif                
+#ifdef POLLNVAL
+  scm_c_define ("POLLNVAL", scm_from_int (POLLNVAL));
+#endif                
+
+}
+
+void
+scm_register_poll (void)
+{
+  scm_c_register_extension ("libguile-" SCM_EFFECTIVE_VERSION,
+                            "scm_init_poll",
+                           (scm_t_extension_init_func) scm_init_poll,
+                           NULL);
+}
+
+/*
+  Local Variables:
+  c-file-style: "gnu"
+  End:
+*/