Add better error checks in mutex support, see https://svn.boost.org/trac/boost/ticket/8903

src/static_mutex.cpp

@@ -18,6 +18,7 @@
 
 #define BOOST_REGEX_SOURCE
 #include <boost/config.hpp>
+#include <boost/assert.hpp>
 
 #ifdef BOOST_HAS_THREADS
 
@@ -54,8 +55,8 @@ void scoped_static_mutex_lock::lock()
 {
    if(0 == m_have_lock)
    {
-      pthread_mutex_lock(&(m_mutex.m_mutex));
-      m_have_lock = true;
+      // Client code will throw if this fails:
+      m_have_lock = (pthread_mutex_lock(&(m_mutex.m_mutex)) == 0);
    }
 }
 
@@ -63,7 +64,10 @@ void scoped_static_mutex_lock::unlock()
 {
    if(m_have_lock)
    {
-      pthread_mutex_unlock(&(m_mutex.m_mutex));
+      // If this fails there's nothing we can do except assert,
+      // exceptions are out of the question as this code is called
+      // from the lock's destructor:
+      BOOST_VERIFY(pthread_mutex_unlock(&(m_mutex.m_mutex)) == 0);
       m_have_lock = false;
    }
 }