Silence all "unused parameter" warnings from Clang.

Compiling without warnings is a good goal, because it makes
new warnings (which probably indicate bugs) stand out rather
than getting lost in the spam.

My fixes fall into two categories:

    - Adding (void) casts of unused parameters, where their
      unusedness seems like a TODO (or in some cases a bug?).

    - Removing parameter names altogether, where the function
      is clearly a stub that will never use its parameters.

Should be no change in behavior.

src/dealer.cpp

@@ -47,6 +47,9 @@ zmq::dealer_t::~dealer_t ()
 
 void zmq::dealer_t::xattach_pipe (pipe_t *pipe_, bool icanhasall_)
 {
+    // icanhasall_ is unused
+    (void) icanhasall_;
+
     zmq_assert (pipe_);
     fq.attach (pipe_);
     lb.attach (pipe_);
@@ -59,6 +62,9 @@ int zmq::dealer_t::xsend (msg_t *msg_, int flags_)
 
 int zmq::dealer_t::xrecv (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     //  If there is a prefetched message, return it.
     if (prefetched) {
         int rc = msg_->move (prefetched_msg);

src/dist.cpp

@@ -128,6 +128,9 @@ int zmq::dist_t::send_to_matching (msg_t *msg_, int flags_)
 
 void zmq::dist_t::distribute (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     //  If there are no matching pipes available, simply drop the message.
     if (matching == 0) {
         int rc = msg_->close ();

src/err.cpp

@@ -72,6 +72,7 @@ void zmq::zmq_abort(const char *errmsg_)
     extra_info [0] = (ULONG_PTR) errmsg_;
     RaiseException (0x40000015, EXCEPTION_NONCONTINUABLE, 1, extra_info);
 #else
+    (void)errmsg_;
     abort ();
 #endif
 }

src/io_object.cpp

@@ -102,7 +102,7 @@ void zmq::io_object_t::out_event ()
     zmq_assert (false);
 }
 
-void zmq::io_object_t::timer_event (int id_)
+void zmq::io_object_t::timer_event (int)
 {
     zmq_assert (false);
 }

src/io_thread.cpp

@@ -85,7 +85,7 @@ void zmq::io_thread_t::out_event ()
     zmq_assert (false);
 }
 
-void zmq::io_thread_t::timer_event (int id_)
+void zmq::io_thread_t::timer_event (int)
 {
     //  No timers here. This function is never called.
     zmq_assert (false);

src/lb.cpp

@@ -73,6 +73,9 @@ void zmq::lb_t::activated (pipe_t *pipe_)
 
 int zmq::lb_t::send (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     //  Drop the message if required. If we are at the end of the message
     //  switch back to non-dropping mode.
     if (dropping) {

src/object.cpp

@@ -316,17 +316,17 @@ void zmq::object_t::process_plug ()
     zmq_assert (false);
 }
 
-void zmq::object_t::process_own (own_t *object_)
+void zmq::object_t::process_own (own_t *)
 {
     zmq_assert (false);
 }
 
-void zmq::object_t::process_attach (i_engine *engine_)
+void zmq::object_t::process_attach (i_engine *)
 {
     zmq_assert (false);
 }
 
-void zmq::object_t::process_bind (pipe_t *pipe_)
+void zmq::object_t::process_bind (pipe_t *)
 {
     zmq_assert (false);
 }
@@ -336,12 +336,12 @@ void zmq::object_t::process_activate_read ()
     zmq_assert (false);
 }
 
-void zmq::object_t::process_activate_write (uint64_t msgs_read_)
+void zmq::object_t::process_activate_write (uint64_t)
 {
     zmq_assert (false);
 }
 
-void zmq::object_t::process_hiccup (void *pipe_)
+void zmq::object_t::process_hiccup (void *)
 {
     zmq_assert (false);
 }
@@ -356,12 +356,12 @@ void zmq::object_t::process_pipe_term_ack ()
     zmq_assert (false);
 }
 
-void zmq::object_t::process_term_req (own_t *object_)
+void zmq::object_t::process_term_req (own_t *)
 {
     zmq_assert (false);
 }
 
-void zmq::object_t::process_term (int linger_)
+void zmq::object_t::process_term (int)
 {
     zmq_assert (false);
 }
@@ -371,7 +371,7 @@ void zmq::object_t::process_term_ack ()
     zmq_assert (false);
 }
 
-void zmq::object_t::process_reap (class socket_base_t *socket_)
+void zmq::object_t::process_reap (class socket_base_t *)
 {
     zmq_assert (false);
 }

src/pair.cpp

@@ -38,6 +38,9 @@ zmq::pair_t::~pair_t ()
 
 void zmq::pair_t::xattach_pipe (pipe_t *pipe_, bool icanhasall_)
 {
+    // icanhasall_ is unused
+    (void)icanhasall_;
+
     zmq_assert (pipe_ != NULL);
 
     //  ZMQ_PAIR socket can only be connected to a single peer.
@@ -54,13 +57,13 @@ void zmq::pair_t::xterminated (pipe_t *pipe_)
         pipe = NULL;
 }
 
-void zmq::pair_t::xread_activated (pipe_t *pipe_)
+void zmq::pair_t::xread_activated (pipe_t *)
 {
     //  There's just one pipe. No lists of active and inactive pipes.
     //  There's nothing to do here.
 }
 
-void zmq::pair_t::xwrite_activated (pipe_t *pipe_)
+void zmq::pair_t::xwrite_activated (pipe_t *)
 {
     //  There's just one pipe. No lists of active and inactive pipes.
     //  There's nothing to do here.
@@ -85,6 +88,9 @@ int zmq::pair_t::xsend (msg_t *msg_, int flags_)
 
 int zmq::pair_t::xrecv (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     //  Deallocate old content of the message.
     int rc = msg_->close ();
     errno_assert (rc == 0);

src/pub.cpp

@@ -32,7 +32,7 @@ zmq::pub_t::~pub_t ()
 {
 }
 
-int zmq::pub_t::xrecv (class msg_t *msg_, int flags_)
+int zmq::pub_t::xrecv (class msg_t *, int)
 {
     //  Messages cannot be received from PUB socket.
     errno = ENOTSUP;

src/pull.cpp

@@ -36,6 +36,9 @@ zmq::pull_t::~pull_t ()
 
 void zmq::pull_t::xattach_pipe (pipe_t *pipe_, bool icanhasall_)
 {
+    // icanhasall_ is unused
+    (void)icanhasall_;
+
     zmq_assert (pipe_);
     fq.attach (pipe_);
 }
@@ -52,6 +55,9 @@ void zmq::pull_t::xterminated (pipe_t *pipe_)
 
 int zmq::pull_t::xrecv (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     return fq.recv (msg_);
 }
 

src/push.cpp

@@ -36,6 +36,9 @@ zmq::push_t::~push_t ()
 
 void zmq::push_t::xattach_pipe (pipe_t *pipe_, bool icanhasall_)
 {
+    // icanhasall_ is unused
+    (void)icanhasall_;
+
     zmq_assert (pipe_);
     lb.attach (pipe_);
 }

src/reaper.cpp

@@ -78,7 +78,7 @@ void zmq::reaper_t::out_event ()
     zmq_assert (false);
 }
 
-void zmq::reaper_t::timer_event (int id_)
+void zmq::reaper_t::timer_event (int)
 {
     zmq_assert (false);
 }

src/router.cpp

@@ -61,6 +61,9 @@ zmq::router_t::~router_t ()
 
 void zmq::router_t::xattach_pipe (pipe_t *pipe_, bool icanhasall_)
 {
+    // icanhasall_ is unused
+    (void)icanhasall_;
+
     zmq_assert (pipe_);
 
     bool identity_ok = identify_peer (pipe_);
@@ -128,6 +131,9 @@ void zmq::router_t::xwrite_activated (pipe_t *pipe_)
 
 int zmq::router_t::xsend (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     //  If this is the first part of the message it's the ID of the
     //  peer to send the message to.
     if (!more_out) {
@@ -193,6 +199,9 @@ int zmq::router_t::xsend (msg_t *msg_, int flags_)
 
 int zmq::router_t::xrecv (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     if (prefetched) {
         if (!identity_sent) {
             int rc = msg_->move (prefetched_id);

src/session_base.cpp

@@ -279,7 +279,7 @@ void zmq::session_base_t::write_activated (pipe_t *pipe_)
         engine->activate_in ();
 }
 
-void zmq::session_base_t::hiccuped (pipe_t *pipe_)
+void zmq::session_base_t::hiccuped (pipe_t *)
 {
     //  Hiccups are always sent from session to socket, not the other
     //  way round.

src/socket_base.cpp

@@ -874,8 +874,7 @@ void zmq::socket_base_t::process_destroy ()
     destroyed = true;
 }
 
-int zmq::socket_base_t::xsetsockopt (int option_, const void *optval_,
-    size_t optvallen_)
+int zmq::socket_base_t::xsetsockopt (int, const void *, size_t)
 {
     errno = EINVAL;
     return -1;
@@ -886,7 +885,7 @@ bool zmq::socket_base_t::xhas_out ()
     return false;
 }
 
-int zmq::socket_base_t::xsend (msg_t *msg_, int flags_)
+int zmq::socket_base_t::xsend (msg_t *, int)
 {
     errno = ENOTSUP;
     return -1;
@@ -897,22 +896,22 @@ bool zmq::socket_base_t::xhas_in ()
     return false;
 }
 
-int zmq::socket_base_t::xrecv (msg_t *msg_, int flags_)
+int zmq::socket_base_t::xrecv (msg_t *, int)
 {
     errno = ENOTSUP;
     return -1;
 }
 
-void zmq::socket_base_t::xread_activated (pipe_t *pipe_)
+void zmq::socket_base_t::xread_activated (pipe_t *)
 {
     zmq_assert (false);
 }
-void zmq::socket_base_t::xwrite_activated (pipe_t *pipe_)
+void zmq::socket_base_t::xwrite_activated (pipe_t *)
 {
     zmq_assert (false);
 }
 
-void zmq::socket_base_t::xhiccuped (pipe_t *pipe_)
+void zmq::socket_base_t::xhiccuped (pipe_t *)
 {
     zmq_assert (false);
 }
@@ -932,7 +931,7 @@ void zmq::socket_base_t::out_event ()
     zmq_assert (false);
 }
 
-void zmq::socket_base_t::timer_event (int id_)
+void zmq::socket_base_t::timer_event (int)
 {
     zmq_assert (false);
 }

src/sub.cpp

@@ -67,7 +67,7 @@ int zmq::sub_t::xsetsockopt (int option_, const void *optval_,
     return rc;
 }
 
-int zmq::sub_t::xsend (msg_t *msg_, int flags_)
+int zmq::sub_t::xsend (msg_t *, int)
 {
     //  Overload the XSUB's send.
     errno = ENOTSUP;

src/tcp.cpp

@@ -63,6 +63,15 @@ void zmq::tune_tcp_socket (fd_t s_)
 
 void zmq::tune_tcp_keepalives (fd_t s_, int keepalive_, int keepalive_cnt_, int keepalive_idle_, int keepalive_intvl_)
 {
+    // These options are used only under certain #ifdefs below.
+    (void)keepalive_;
+    (void)keepalive_cnt_;
+    (void)keepalive_idle_;
+    (void)keepalive_intvl_;
+
+    // If none of the #ifdefs apply, then s_ is unused.
+    (void)s_;
+
     //  Tuning TCP keep-alives if platform allows it
     //  All values = -1 means skip and leave it for OS
 #ifdef ZMQ_HAVE_SO_KEEPALIVE

src/tcp_address.cpp

@@ -488,7 +488,7 @@ zmq::tcp_address_mask_t::tcp_address_mask_t () :
     address_mask = -1;
 }
 
-const int zmq::tcp_address_mask_t::mask () const
+int zmq::tcp_address_mask_t::mask () const
 {
     return address_mask;
 }
@@ -574,7 +574,7 @@ int zmq::tcp_address_mask_t::to_string (std::string &addr_)
     return 0;
 }
 
-const bool zmq::tcp_address_mask_t::match_address (const struct sockaddr *ss, const socklen_t ss_len) const
+bool zmq::tcp_address_mask_t::match_address (const struct sockaddr *ss, const socklen_t ss_len) const
 {
     zmq_assert (address_mask != -1 && ss != NULL && ss_len >= (socklen_t) sizeof (struct sockaddr));
 

src/tcp_address.hpp

@@ -86,9 +86,9 @@ namespace zmq
         // The opposite to resolve()
         int to_string (std::string &addr_);
 
-        const int mask () const;
+        int mask () const;
 
-        const bool match_address (const struct sockaddr *ss, const socklen_t ss_len) const;
+        bool match_address (const struct sockaddr *ss, const socklen_t ss_len) const;
 
     private:
 

src/tcp_listener.cpp

@@ -238,7 +238,7 @@ zmq::fd_t zmq::tcp_listener_t::accept ()
     //  Accept one connection and deal with different failure modes.
     zmq_assert (s != retired_fd);
 
-    struct sockaddr_storage ss = {0};
+    struct sockaddr_storage ss = {};
 #ifdef ZMQ_HAVE_HPUX
     int ss_len = sizeof (ss);
 #else

src/xpub.cpp

@@ -131,6 +131,9 @@ bool zmq::xpub_t::xhas_out ()
 
 int zmq::xpub_t::xrecv (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     //  If there is at least one 
     if (pending.empty ()) {
         errno = EAGAIN;

src/xsub.cpp

@@ -47,6 +47,9 @@ zmq::xsub_t::~xsub_t ()
 
 void zmq::xsub_t::xattach_pipe (pipe_t *pipe_, bool icanhasall_)
 {
+    // icanhasall_ is unused
+    (void)icanhasall_;
+
     zmq_assert (pipe_);
     fq.attach (pipe_);
     dist.attach (pipe_);
@@ -116,6 +119,9 @@ bool zmq::xsub_t::xhas_out ()
 
 int zmq::xsub_t::xrecv (msg_t *msg_, int flags_)
 {
+    // flags_ is unused
+    (void)flags_;
+
     //  If there's already a message prepared by a previous call to zmq_poll,
     //  return it straight ahead.
     if (has_message) {

src/zmq.cpp

@@ -602,7 +602,7 @@ int zmq_msg_get (zmq_msg_t *msg_, int option_)
     }
 }
 
-int zmq_msg_set (zmq_msg_t *msg_, int option_, int optval_)
+int zmq_msg_set (zmq_msg_t *, int, int)
 {
     //  No options supported at present
     errno = EINVAL;