From 00ae711cd71c9163bdbcd5c3b972477b4d114592 Mon Sep 17 00:00:00 2001
From: Oliver Kowalke <oliver.kowalke@gmx.de>
Date: Wed, 16 Sep 2015 22:11:11 +0200
Subject: [PATCH] join only non-terminated fibers

- context::join() adds active-context to wait-queue only
  if joined context is not terminated
- we can not use terminated_is_linked() because the context
  might already be removed from scheudler's termianted-queue
---
 include/boost/fiber/context.hpp |  3 ++-
 src/context.cpp                 | 20 ++++++++++++--------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/include/boost/fiber/context.hpp b/include/boost/fiber/context.hpp
index 615cfd93..0773f6e2 100644
--- a/include/boost/fiber/context.hpp
+++ b/include/boost/fiber/context.hpp
@@ -101,7 +101,8 @@ private:
     enum flag_t {
         flag_main_context       = 1 << 1,
         flag_dispatcher_context = 1 << 2,
-        flag_worker_context     = 1 << 3
+        flag_worker_context     = 1 << 3,
+        flag_terminated         = 1 << 4
     };
 
     static thread_local context         *   active_;
diff --git a/src/context.cpp b/src/context.cpp
index 59e32b5f..ecd2d7c3 100644
--- a/src/context.cpp
+++ b/src/context.cpp
@@ -44,6 +44,7 @@ context::active( context * active) noexcept {
 
 void
 context::set_terminated_() noexcept {
+    flags_ |= flag_terminated;
     scheduler_->set_terminated( this);
 }
 
@@ -127,14 +128,17 @@ context::release() noexcept {
 
 void
 context::join() noexcept {
-    // get active context
-    context * active_ctx = context::active();
-    // push active context to wait-queue, member
-    // of the context which has to be joined by
-    // the active context
-    wait_queue_.push_back( * active_ctx);
-    // suspend active context
-    scheduler_->re_schedule( active_ctx);
+    // wait for context which is not terminated
+    if ( 0 == ( flags_ & flag_terminated) ) {
+        // get active context
+        context * active_ctx = context::active();
+        // push active context to wait-queue, member
+        // of the context which has to be joined by
+        // the active context
+        wait_queue_.push_back( * active_ctx);
+        // suspend active context
+        scheduler_->re_schedule( active_ctx);
+    }
 }
 
 bool