diff --git a/src/c++wrap.hh b/src/c++wrap.hh
index 4de83aa7..6b93c1a6 100644
--- a/src/c++wrap.hh
+++ b/src/c++wrap.hh
@@ -24,7 +24,7 @@
 #ifndef CPPWRAP_HH
 #define CPPWRAP_HH
 
-#include <unistd.h>
+#include <fcntl.h>
 
 #include <cerrno>
 #include <stdexcept>
diff --git a/src/update-cb.cc b/src/update-cb.cc
index b2f9009f..985c8452 100644
--- a/src/update-cb.cc
+++ b/src/update-cb.cc
@@ -39,9 +39,15 @@ namespace conky {
 			if(thread) {
 				done = true;
 				sem_start.post();
+				if(pipefd.second >= 0)
+					write(pipefd.second, "X", 1);
 				thread->join();
 				delete thread;
 			}
+			if(pipefd.first >= 0)
+				close(pipefd.first);
+			if(pipefd.second >= 0)
+				close(pipefd.second);
 		}
 
 		inline size_t callback_base::get_hash(const handle &h)
diff --git a/src/update-cb.hh b/src/update-cb.hh
index 83e72554..2bc8df4d 100644
--- a/src/update-cb.hh
+++ b/src/update-cb.hh
@@ -32,6 +32,7 @@
 
 #include <assert.h>
 
+#include "c++wrap.hh"
 #include "semaphore.hh"
 
 namespace conky {
@@ -55,6 +56,7 @@ namespace conky {
 			const size_t hash;
 			uint32_t period;
 			uint32_t remaining;
+			std::pair<int, int> pipefd;
 			const bool wait;
 			bool done;
 			uint8_t unused;
@@ -83,11 +85,15 @@ namespace conky {
 			friend void conky::run_all_callbacks();
 
 		protected:
-			callback_base(size_t hash_, uint32_t period_, bool wait_)
-				: thread(NULL), hash(hash_), period(period_), remaining(0), wait(wait_),
-				  done(false), unused(0)
+			callback_base(size_t hash_, uint32_t period_, bool wait_, bool use_pipe = false)
+				: thread(NULL), hash(hash_), period(period_), remaining(0),
+				  pipefd(use_pipe ? pipe2(O_CLOEXEC) : std::pair<int, int>(-1, -1)),
+				  wait(wait_), done(false), unused(0)
 			{}
 
+			int donefd()
+			{ return pipefd.first; }
+
 			// to be implemented by descendant classes
 			virtual void work() = 0;