diff --git a/lib/cpp/src/thrift/concurrency/Thread.h b/lib/cpp/src/thrift/concurrency/Thread.h
index 729d11a..cacd401 100644
--- a/lib/cpp/src/thrift/concurrency/Thread.h
+++ b/lib/cpp/src/thrift/concurrency/Thread.h
@@ -153,7 +153,7 @@
   /**
    * Gets the thread's platform-specific ID
    */
-  Thread::id_t getId() { return thread_.get() ? thread_->get_id() : std::thread::id(); }
+  Thread::id_t getId() const { return thread_.get() ? thread_->get_id() : std::thread::id(); }
 
   /**
    * Gets the runnable object this thread is hosting
diff --git a/lib/cpp/src/thrift/concurrency/ThreadManager.cpp b/lib/cpp/src/thrift/concurrency/ThreadManager.cpp
index 58025f9..5e88327 100644
--- a/lib/cpp/src/thrift/concurrency/ThreadManager.cpp
+++ b/lib/cpp/src/thrift/concurrency/ThreadManager.cpp
@@ -110,7 +110,7 @@
     return pendingTaskCountMax_;
   }
 
-  size_t expiredTaskCount() {
+  size_t expiredTaskCount() const {
     Guard g(mutex_);
     return expiredCount_;
   }
diff --git a/lib/cpp/src/thrift/concurrency/ThreadManager.h b/lib/cpp/src/thrift/concurrency/ThreadManager.h
index 4b4b3d4..605e363 100644
--- a/lib/cpp/src/thrift/concurrency/ThreadManager.h
+++ b/lib/cpp/src/thrift/concurrency/ThreadManager.h
@@ -22,7 +22,6 @@
 
 #include <functional>
 #include <memory>
-#include <sys/types.h>
 #include <thrift/concurrency/ThreadFactory.h>
 
 namespace apache {
@@ -141,7 +140,7 @@
    * Gets the number of tasks which have been expired without being run
    * since start() was called.
    */
-  virtual size_t expiredTaskCount() = 0;
+  virtual size_t expiredTaskCount() const = 0;
 
   /**
    * Adds a task to be executed at some time in the future by a worker thread.
diff --git a/lib/cpp/src/thrift/transport/TTransport.h b/lib/cpp/src/thrift/transport/TTransport.h
index d844239..d300f6b 100644
--- a/lib/cpp/src/thrift/transport/TTransport.h
+++ b/lib/cpp/src/thrift/transport/TTransport.h
@@ -63,7 +63,7 @@
   /**
    * Whether this transport is open.
    */
-  virtual bool isOpen() { return false; }
+  virtual bool isOpen() const { return false; }
 
   /**
    * Tests whether there is more data to read or if the remote side is
@@ -73,7 +73,7 @@
    * This is used by a server to check if it should listen for another
    * request.
    */
-  virtual bool peek() { return isOpen(); }
+  virtual bool peek() const { return isOpen(); }
 
   /**
    * Opens the transport for communications.