diff --git a/docs/doxygen/other/thread_affinity.dox b/docs/doxygen/other/thread_affinity.dox

index edac813..03d2129 100644

--- a/docs/doxygen/other/thread_affinity.dox

+++ b/docs/doxygen/other/thread_affinity.dox

@@ -50,7 +50,7 @@ Each block has two new data members:

 A block can set and unset its affinity at any time using the

 following member functions:

-- gr::block::set_processor_affinity(const std::vector<int> &mask)

+- gr::block::set_processor_affinity(const std::vector<std::size_t> &mask)

 - gr::block::unset_processor_affinity()

 Where \p mask is a vector of core numbers to set the thread's affinity

@@ -76,7 +76,7 @@ to that affinity setting.

 The gr::hier_block2 class supports the same API interface to the block

 thread affinity:

-- gr::hier_block2::set_processor_affinity(const std::vector<int> &mask)

+- gr::hier_block2::set_processor_affinity(const std::vector<std::size_t> &mask)

 - gr::hier_block2::unset_processor_affinity()

 - gr::hier_block2::processor_affinity()

diff --git a/gnuradio-runtime/include/gnuradio/basic_block.h b/gnuradio-runtime/include/gnuradio/basic_block.h

index 25d9fb5..2a43a8a 100644

--- a/gnuradio-runtime/include/gnuradio/basic_block.h

+++ b/gnuradio-runtime/include/gnuradio/basic_block.h

@@ -376,13 +376,13 @@ namespace gr {

       d_msg_handlers[which_port] = msg_handler_t(msg_handler);

     }

-    virtual void set_processor_affinity(const std::vector<int> &mask)

+    virtual void set_processor_affinity(const std::vector<std::size_t> &mask)

     { throw std::runtime_error("set_processor_affinity not overloaded in child class."); }

     virtual void unset_processor_affinity()

     { throw std::runtime_error("unset_processor_affinity not overloaded in child class."); }

-    virtual std::vector<int> processor_affinity()

+    virtual std::vector<std::size_t> processor_affinity()

     { throw std::runtime_error("processor_affinity not overloaded in child class."); }

   };

diff --git a/gnuradio-runtime/include/gnuradio/block.h b/gnuradio-runtime/include/gnuradio/block.h

index c6185d9..8480ec7 100644

--- a/gnuradio-runtime/include/gnuradio/block.h

+++ b/gnuradio-runtime/include/gnuradio/block.h

@@ -593,9 +593,9 @@ namespace gr {

     /*!

      * \brief Set the thread's affinity to processor core \p n.

      *

-     * \param mask a vector of ints of the core numbers available to this block.

+     * \param mask a vector of std::size_t of the core numbers available to this block.

      */

-    void set_processor_affinity(const std::vector<int> &mask);

+    void set_processor_affinity(const std::vector<std::size_t> &mask);

     /*!

      * \brief Remove processor affinity to a specific core.

@@ -605,7 +605,7 @@ namespace gr {

     /*!

      * \brief Get the current processor affinity.

      */

-    std::vector<int> processor_affinity() { return d_affinity; }

+    std::vector<std::size_t> processor_affinity() { return d_affinity; }

     /*!

      * \brief Get the current thread priority in use

@@ -650,7 +650,7 @@ namespace gr {

     int                   d_max_noutput_items;         // value of max_noutput_items for this block

     int                   d_min_noutput_items;

     tag_propagation_policy_t d_tag_propagation_policy; // policy for moving tags downstream

-    std::vector<int>      d_affinity;              // thread affinity proc. mask

+    std::vector<std::size_t>      d_affinity;              // thread affinity proc. mask

     int                   d_priority;              // thread priority level

     bool                  d_pc_rpc_set;

     bool                  d_update_rate;           // should sched update rel rate?

diff --git a/gnuradio-runtime/include/gnuradio/block_detail.h b/gnuradio-runtime/include/gnuradio/block_detail.h

index 916c0a4..1d52824 100644

--- a/gnuradio-runtime/include/gnuradio/block_detail.h

+++ b/gnuradio-runtime/include/gnuradio/block_detail.h

@@ -174,10 +174,10 @@ namespace gr {

      * \brief Set core affinity of block to the cores in the vector

      * mask.

      *

-     * \param mask a vector of ints of the core numbers available to

+     * \param mask a vector of std::size_t of the core numbers available to

      * this block.

      */

-    void set_processor_affinity(const std::vector<int> &mask);

+    void set_processor_affinity(const std::vector<std::size_t> &mask);

     /*!

      * \brief Unset core affinity.

diff --git a/gnuradio-runtime/include/gnuradio/hier_block2.h b/gnuradio-runtime/include/gnuradio/hier_block2.h

index 08a5389..d4f9696 100644

--- a/gnuradio-runtime/include/gnuradio/hier_block2.h

+++ b/gnuradio-runtime/include/gnuradio/hier_block2.h

@@ -248,7 +248,7 @@ namespace gr {

      *

      * \param mask a vector of ints of the core numbers available to this block.

      */

-    void set_processor_affinity(const std::vector<int> &mask);

+    void set_processor_affinity(const std::vector<std::size_t> &mask);

     /*!

      * \brief Remove processor affinity for all blocks in hier_block2.

@@ -264,7 +264,7 @@ namespace gr {

      * interface. If any block has been individually set, then this

      * call could be misleading.

      */

-    std::vector<int> processor_affinity();

+    std::vector<std::size_t> processor_affinity();

     /*!

      * \brief Get if all block min buffers should be set.

diff --git a/gnuradio-runtime/include/gnuradio/thread/thread.h b/gnuradio-runtime/include/gnuradio/thread/thread.h

index a58d172..6c6c1bf 100644

--- a/gnuradio-runtime/include/gnuradio/thread/thread.h

+++ b/gnuradio-runtime/include/gnuradio/thread/thread.h

@@ -77,7 +77,7 @@ namespace gr {

      * do support in this way since 10.5 is not what we want or can

      * use in this fashion).

      */

-    GR_RUNTIME_API void thread_bind_to_processor(const std::vector<int> &mask);

+    GR_RUNTIME_API void thread_bind_to_processor(const std::vector<std::size_t> &mask);

     /*! \brief Convineince function to bind the current thread to a single core.

      *

@@ -89,7 +89,7 @@ namespace gr {

      * do support in this way since 10.5 is not what we want or can

      * use in this fashion).

      */

-    GR_RUNTIME_API void thread_bind_to_processor(int n);

+    GR_RUNTIME_API void thread_bind_to_processor(std::size_t n);

     /*! \brief Bind a thread to a set of cores.

      *

@@ -104,7 +104,7 @@ namespace gr {

      * use in this fashion).

      */

     GR_RUNTIME_API void thread_bind_to_processor(gr_thread_t thread,

-                                                 const std::vector<int> &mask);

+                                                 const std::vector<std::size_t> &mask);

     /*! \brief Convineince function to bind the a thread to a single core.

diff --git a/gnuradio-runtime/lib/block.cc b/gnuradio-runtime/lib/block.cc

index 2bae8ea..9641022 100644

--- a/gnuradio-runtime/lib/block.cc

+++ b/gnuradio-runtime/lib/block.cc

@@ -325,7 +325,7 @@ namespace gr {

   }

   void

-  block::set_processor_affinity(const std::vector<int> &mask)

+  block::set_processor_affinity(const std::vector<std::size_t> &mask)

   {

     d_affinity = mask;

     if(d_detail) {

diff --git a/gnuradio-runtime/lib/block_detail.cc b/gnuradio-runtime/lib/block_detail.cc

index 9463e8d..96b54d0 100644

--- a/gnuradio-runtime/lib/block_detail.cc

+++ b/gnuradio-runtime/lib/block_detail.cc

@@ -223,7 +223,7 @@ namespace gr {

   }

   void

-  block_detail::set_processor_affinity(const std::vector<int> &mask)

+  block_detail::set_processor_affinity(const std::vector<std::size_t> &mask)

   {

     if(threaded) {

       try {

diff --git a/gnuradio-runtime/lib/hier_block2.cc b/gnuradio-runtime/lib/hier_block2.cc

index 597ae03..031ec30 100644

--- a/gnuradio-runtime/lib/hier_block2.cc

+++ b/gnuradio-runtime/lib/hier_block2.cc

@@ -161,7 +161,7 @@ namespace gr {

   }

   void

-  hier_block2::set_processor_affinity(const std::vector<int> &mask)

+  hier_block2::set_processor_affinity(const std::vector<std::size_t> &mask)

   {

     d_detail->set_processor_affinity(mask);

   }

@@ -172,7 +172,7 @@ namespace gr {

     d_detail->unset_processor_affinity();

   }

-  std::vector<int>

+  std::vector<std::size_t>

   hier_block2::processor_affinity()

   {

     return d_detail->processor_affinity();

diff --git a/gnuradio-runtime/lib/hier_block2_detail.cc b/gnuradio-runtime/lib/hier_block2_detail.cc

index 0d0ddf5..175e787 100644

--- a/gnuradio-runtime/lib/hier_block2_detail.cc

+++ b/gnuradio-runtime/lib/hier_block2_detail.cc

@@ -932,7 +932,7 @@ namespace gr {

   }

   void

-  hier_block2_detail::set_processor_affinity(const std::vector<int> &mask)

+  hier_block2_detail::set_processor_affinity(const std::vector<std::size_t> &mask)

   {

     basic_block_vector_t tmp = d_fg->calc_used_blocks();

     for(basic_block_viter_t p = tmp.begin(); p != tmp.end(); p++) {

@@ -949,7 +949,7 @@ namespace gr {

     }

   }

-  std::vector<int>

+  std::vector<std::size_t>

   hier_block2_detail::processor_affinity()

   {

     basic_block_vector_t tmp = d_fg->calc_used_blocks();

diff --git a/gnuradio-runtime/lib/hier_block2_detail.h b/gnuradio-runtime/lib/hier_block2_detail.h

index a5584fe..0cdb149 100644

--- a/gnuradio-runtime/lib/hier_block2_detail.h

+++ b/gnuradio-runtime/lib/hier_block2_detail.h

@@ -54,9 +54,9 @@ namespace gr {

     void unlock();

     void flatten_aux(flat_flowgraph_sptr sfg) const;

-    void set_processor_affinity(const std::vector<int> &mask);

+    void set_processor_affinity(const std::vector<std::size_t> &mask);

     void unset_processor_affinity();

-    std::vector<int> processor_affinity();

+    std::vector<std::size_t> processor_affinity();

     // Track output buffer min/max settings

     std::vector<size_t> d_max_output_buffer;

diff --git a/gnuradio-runtime/lib/thread/thread.cc b/gnuradio-runtime/lib/thread/thread.cc

index 483dfed..e05a8ba 100644

--- a/gnuradio-runtime/lib/thread/thread.cc

+++ b/gnuradio-runtime/lib/thread/thread.cc

@@ -40,33 +40,33 @@ namespace gr {

     }

     void

-    thread_bind_to_processor(int n)

+    thread_bind_to_processor(std::size_t n)

     {

-      std::vector<int> mask(1, n);

+      std::vector<std::size_t> mask(1, n);

       thread_bind_to_processor(get_current_thread_id(), mask);

     }

     void

-    thread_bind_to_processor(const std::vector<int> &mask)

+    thread_bind_to_processor(const std::vector<std::size_t> &mask)

     {

       thread_bind_to_processor(get_current_thread_id(), mask);

     }

     void

-    thread_bind_to_processor(gr_thread_t thread, int n)

+    thread_bind_to_processor(gr_thread_t thread, std::size_t n)

     {

-      std::vector<int> mask(1, n);

+      std::vector<std::size_t> mask(1, n);

       thread_bind_to_processor(thread, mask);

     }

     void

-    thread_bind_to_processor(gr_thread_t thread, const std::vector<int> &mask)

+    thread_bind_to_processor(gr_thread_t thread, const std::vector<std::size_t> &mask)

     {

       //DWORD_PTR mask = (1 << n);

       DWORD_PTR dword_mask = 0;

-      std::vector<int> _mask = mask;

-      std::vector<int>::iterator itr;

+      std::vector<std::size_t> _mask = mask;

+      std::vector<std::size_t>::iterator itr;

       for(itr = _mask.begin(); itr != _mask.end(); itr++)

         dword_mask |= (1 << (*itr));

@@ -171,25 +171,25 @@ namespace gr {

     }

     void

-    thread_bind_to_processor(int n)

+    thread_bind_to_processor(std::size_t n)

     {

       // Not implemented on OSX

     }

     void

-    thread_bind_to_processor(gr_thread_t thread, int n)

+    thread_bind_to_processor(gr_thread_t thread, std::size_t n)

     {

       // Not implemented on OSX

     }

     void

-    thread_bind_to_processor(const std::vector<int> &mask)

+    thread_bind_to_processor(const std::vector<std::size_t> &mask)

     {

       // Not implemented on OSX

     }

     void

-    thread_bind_to_processor(gr_thread_t thread, const std::vector<int> &mask)

+    thread_bind_to_processor(gr_thread_t thread, const std::vector<std::size_t> &mask)

     {

       // Not implemented on OSX

     }

@@ -254,32 +254,32 @@ namespace gr {

     }

     void

-    thread_bind_to_processor(int n)

+    thread_bind_to_processor(std::size_t n)

     {

-      std::vector<int> mask(1, n);

+      std::vector<std::size_t> mask(1, n);

       thread_bind_to_processor(get_current_thread_id(), mask);

     }

     void

-    thread_bind_to_processor(const std::vector<int> &mask)

+    thread_bind_to_processor(const std::vector<std::size_t> &mask)

     {

       thread_bind_to_processor(get_current_thread_id(), mask);

     }

     void

-    thread_bind_to_processor(gr_thread_t thread, int n)

+    thread_bind_to_processor(gr_thread_t thread, std::size_t n)

     {

-      std::vector<int> mask(1, n);

+      std::vector<std::size_t> mask(1, n);

       thread_bind_to_processor(thread, mask);

     }

     void

-    thread_bind_to_processor(gr_thread_t thread, const std::vector<int> &mask)

+    thread_bind_to_processor(gr_thread_t thread, const std::vector<std::size_t> &mask)

     {

       cpu_set_t set;

       size_t len = sizeof(cpu_set_t);

-      std::vector<int> _mask = mask;

-      std::vector<int>::iterator itr;

+      std::vector<std::size_t> _mask = mask;

+      std::vector<std::size_t>::iterator itr;

       CPU_ZERO(&set);

       for(itr = _mask.begin(); itr != _mask.end(); itr++)

diff --git a/gnuradio-runtime/swig/block.i b/gnuradio-runtime/swig/block.i

index 945cea7..7d2b29e 100644

--- a/gnuradio-runtime/swig/block.i

+++ b/gnuradio-runtime/swig/block.i

@@ -99,9 +99,9 @@ class gr::block : public gr::basic_block

   float pc_throughput_avg();

   // Methods to manage processor affinity.

-  void set_processor_affinity(const std::vector<int> &mask);

+  void set_processor_affinity(const std::vector<std::size_t> &mask);

   void unset_processor_affinity();

-  std::vector<int> processor_affinity();

+  std::vector<std::size_t> processor_affinity();

   // Methods to manage thread priority

   int active_thread_priority();

diff --git a/gnuradio-runtime/swig/hier_block2.i b/gnuradio-runtime/swig/hier_block2.i

index 12190d0..de79e3f 100644

--- a/gnuradio-runtime/swig/hier_block2.i

+++ b/gnuradio-runtime/swig/hier_block2.i

@@ -87,9 +87,9 @@ namespace gr {

     void message_port_register_hier_in(pmt::pmt_t port_id);

     void message_port_register_hier_out(pmt::pmt_t port_id);

-    void set_processor_affinity(const std::vector<int> &mask);

+    void set_processor_affinity(const std::vector<std::size_t> &mask);

     void unset_processor_affinity();

-    std::vector<int> processor_affinity();

+    std::vector<std::size_t> processor_affinity();

     // Methods to manage block's min/max buffer sizes.

     size_t max_output_buffer(int i);

diff --git a/gr-blocks/lib/qa_gr_top_block.cc b/gr-blocks/lib/qa_gr_top_block.cc

index 39709d2..8792637 100644

--- a/gr-blocks/lib/qa_gr_top_block.cc

+++ b/gr-blocks/lib/qa_gr_top_block.cc

@@ -278,7 +278,7 @@ void qa_top_block::t11_set_block_affinity()

   gr::block_sptr src (gr::blocks::null_source::make(sizeof(float)));

   gr::block_sptr snk (gr::blocks::null_sink::make(sizeof(float)));

-  std::vector<int> set(1, 0), ret;

+  std::vector<std::size_t> set(1, 0), ret;

   src->set_processor_affinity(set);

   tb->connect(src, 0, snk, 0);