Fix undefined reference in Ruby code, add linker warning

src/ruby/ext/grpc/extconf.rb

@@ -92,6 +92,7 @@ if grpc_config == 'gcov'
 end
 
 $LDFLAGS << ' -Wl,-wrap,memcpy' if RUBY_PLATFORM =~ /linux/
+$LDFLAGS << ' -Wl,--no-undefined'
 $LDFLAGS << ' -static' if windows
 
 $CFLAGS << ' -std=c99 '

src/ruby/ext/grpc/rb_channel.c

@@ -40,6 +40,7 @@
 #include <grpc/grpc_security.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
+#include <grpc/support/time.h>
 #include "rb_grpc.h"
 #include "rb_call.h"
 #include "rb_channel_args.h"
@@ -71,6 +72,7 @@ typedef struct grpc_rb_channel {
 
   /* The actual channel */
   grpc_channel *wrapped;
+  grpc_completion_queue *queue;
 } grpc_rb_channel;
 
 /* Destroys Channel instances. */
@@ -83,6 +85,7 @@ static void grpc_rb_channel_free(void *p) {
 
   if (ch->wrapped != NULL) {
     grpc_channel_destroy(ch->wrapped);
+    grpc_rb_completion_queue_destroy(ch->queue);
   }
 
   xfree(p);
@@ -165,6 +168,7 @@ static VALUE grpc_rb_channel_init(int argc, VALUE *argv, VALUE self) {
   }
   rb_ivar_set(self, id_target, target);
   wrapper->wrapped = ch;
+  wrapper->queue = grpc_completion_queue_create(NULL);
   return self;
 }
 
@@ -203,16 +207,18 @@ static VALUE grpc_rb_channel_get_connectivity_state(int argc, VALUE *argv,
    the completion queue with success=0 */
 static VALUE grpc_rb_channel_watch_connectivity_state(VALUE self,
                                                       VALUE last_state,
-                                                      VALUE cqueue,
-                                                      VALUE deadline,
-                                                      VALUE tag) {
+                                                      VALUE deadline) {
   grpc_rb_channel *wrapper = NULL;
   grpc_channel *ch = NULL;
   grpc_completion_queue *cq = NULL;
 
-  cq = grpc_rb_get_wrapped_completion_queue(cqueue);
+  void *tag = wrapper;
+
+  grpc_event event;
+
   TypedData_Get_Struct(self, grpc_rb_channel, &grpc_channel_data_type, wrapper);
   ch = wrapper->wrapped;
+  cq = wrapper->queue;
   if (ch == NULL) {
     rb_raise(rb_eRuntimeError, "closed!");
     return Qnil;
@@ -222,9 +228,16 @@ static VALUE grpc_rb_channel_watch_connectivity_state(VALUE self,
       (grpc_connectivity_state)NUM2LONG(last_state),
       grpc_rb_time_timeval(deadline, /* absolute time */ 0),
       cq,
-      ROBJECT(tag));
+      tag);
 
-  return Qnil;
+  event = rb_completion_queue_pluck(cq, tag,
+                                    gpr_inf_future(GPR_CLOCK_REALTIME), NULL);
+
+  if (event.success) {
+    return Qtrue;
+  } else {
+    return Qfalse;
+  }
 }
 
 /* Create a call given a grpc_channel, in order to call method. The request

src/ruby/ext/grpc/rb_completion_queue.h

@@ -38,9 +38,6 @@
 
 #include <grpc/grpc.h>
 
-/* Gets the wrapped completion queue from the ruby wrapper */
-grpc_completion_queue *grpc_rb_get_wrapped_completion_queue(VALUE v);
-
 void grpc_rb_completion_queue_destroy(grpc_completion_queue *cq);
 
 /**