From 2eccdda3c595ca3ef4086f37a1a350c1cfea54b3 Mon Sep 17 00:00:00 2001
From: tqchen <tianqi.tchen@gmail.com>
Date: Mon, 27 Apr 2015 22:42:01 -0700
Subject: [PATCH] strict cstyle pthread

---
 src/utils/thread.h        | 22 ++++++++++++++++++++--
 src/utils/thread_buffer.h |  2 +-
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/src/utils/thread.h b/src/utils/thread.h
index 14c27a785..ef6335a74 100644
--- a/src/utils/thread.h
+++ b/src/utils/thread.h
@@ -123,16 +123,33 @@ class Semaphore {
   #endif  
 };
 
+// helper for c thread
+// used to strictly call c++ function from pthread
+struct ThreadContext {
+  void *(*entry)(void*);
+  void *param;
+};
+extern "C" {
+  inline void *RunThreadContext(void *ctx_) {
+    ThreadContext *ctx = reinterpret_cast<ThreadContext*>(ctx_);
+    void *ret = (*ctx->entry)(ctx->param);
+    delete ctx;
+    return ret;
+  }
+}
 /*!\brief simple thread class */
 class Thread {
  private:
   pthread_t thread;                
+
  public :
-  inline void Start(void * entry(void*), void *param) {
+  inline void Start(void *entry(void*), void *param) {
     pthread_attr_t attr;
     pthread_attr_init(&attr);
     pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
-    pthread_create(&thread, &attr, entry, param);
+    ThreadContext *ctx = new ThreadContext();
+    ctx->entry = entry; ctx->param = param;
+    pthread_create(&thread, &attr, RunThreadContext, ctx);
   }
   inline int Join(void) {
     void *status;
@@ -142,6 +159,7 @@ class Thread {
 inline void ThreadExit(void *status) {
   pthread_exit(status);
 }
+
 }  // namespace utils
 }  // namespace xgboost
 #define XGBOOST_THREAD_PREFIX void *
diff --git a/src/utils/thread_buffer.h b/src/utils/thread_buffer.h
index 2bf365ae2..45da6ec84 100644
--- a/src/utils/thread_buffer.h
+++ b/src/utils/thread_buffer.h
@@ -167,7 +167,6 @@ class ThreadBuffer {
   /*!\brief entry point of loader thread */
   inline static XGBOOST_THREAD_PREFIX LoaderEntry(void *pthread) {
     static_cast< ThreadBuffer<Elem,ElemFactory>* >(pthread)->RunLoader();
-    ThreadExit(NULL);
     return NULL;
   }
   /*!\brief start loader thread */
@@ -199,6 +198,7 @@ class ThreadBuffer {
     loading_need.Post();
   }
 };
+
 }  // namespace utils
 }  // namespace xgboost
 #endif