[Boost-bugs] [Boost C++ Libraries] #5260: scope_guard safe_execute could support try/catch when BOOST_NO_EXCPTIONS not defined

Subject: [Boost-bugs] [Boost C++ Libraries] #5260: scope_guard safe_execute could support try/catch when BOOST_NO_EXCPTIONS not defined
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2011-03-03 20:36:49

#5260: scope_guard safe_execute could support try/catch when BOOST_NO_EXCPTIONS
not defined
------------------------------+---------------------------------------------
 Reporter:  z_gerg@…          |       Owner:  joaquin    
     Type:  Bugs              |      Status:  new        
Milestone:  To Be Determined  |   Component:  multi_index
  Version:  Boost 1.46.0      |    Severity:  Problem    
 Keywords:                    |  
------------------------------+---------------------------------------------
 Hi,

 Since I use boost library for many things, I thought I would take
 advantage of the scope guard implementation in
 boost/multi_index/detail/scope_guard.hpp. I know that is not standard
 practice, but thought it would be better then implementing my own ;-)

 However I discovered the hard way (got an unhandled exception) that
 safe_execute does not support try/catch. From the comments

 *   - safe_execute does not feature a try-catch protection, so we can
 *     use this even if BOOST_NO_EXCEPTIONS is defined.

 I verified that this is still the case in the latest release version. (I
 use an older version).

 It seems it could support try/catch while still honoring
 BOOST_NO_EXCEPTIONS when defined by wrapping the try and catch portions in
 #ifdefs as follows

   template<typename J>
   static void safe_execute(J& j)
   {
       if(!j.dismissed_)
   #ifndef BOOST_NO_EXCEPTIONS
           try {
   #endif
               j.execute();
   #ifndef BOOST_NO_EXCEPTIONS
           } catch (...) {
           }
   #endif
   }

 By doing that when using exceptions it will work as the original code this
 is based on works. And when BOOST_NO_EXCEPTIONS is defined it will work as
 it does now.

 The following example code will generate an unhandled exception with out
 the above mods. The same example with the above mods will also generate
 the unhandled exception if BOOST_NO_EXCEPTIONS is defined (you can
 uncomment the #define BOOST_NO_EXCEPTIONS to test that). It will not
 generate an unhandled exception when BOOST_NO_EXCEPTIONS is not defined.

 // #define BOOST_NO_EXCEPTIONS
 #include <iostream>
 #include <boost/multi_index/detail/scope_guard.hpp>

 void bar()
 {
     throw std::exception("testing");
 }

 void foo()
 {
     boost::multi_index::detail::scope_guard barGuard =
 boost::multi_index::detail::make_guard(&bar);
 }

 int main(int argc, char* argv[])
 {
     foo();
     return 0;
 }

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/5260>
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