add positive infinity test case

In my recent effort to upgrade from boost 1.69 I discovered a change of behavior after the commit 30d5005ac627b36c122e69c86cf518aaaadd92ab. Is my expectation of boost::posix_time::pos_infin to pass the check in semaphore_wrapper incorrect?

One example of a public library relying on pos_infin Fast-DDS

Attempts to build the library with a recent boost results in:

boost/interprocess/sync/posix/semaphore_wrapper.hpp:226:21: error: no matching function for call to 'timepoint_to_timespec'
   timespec tspec = timepoint_to_timespec(abs_time);
                    ^~~~~~~~~~~~~~~~~~~~~
boost/interprocess/sync/posix/semaphore.hpp:55:14: note: in instantiation of function template specialization 'boost::interprocess::ipcdetail::semaphore_timed_wait<boost::date_time::special_values>' requested here
   {  return semaphore_timed_wait(&m_sem, abs_time); }
             ^
boost/interprocess/sync/interprocess_semaphore.hpp:133:16: note: in instantiation of function template specialization 'boost::interprocess::ipcdetail::posix_semaphore::timed_wait<boost::date_time::special_values>' requested here
{ return m_sem.timed_wait(abs_time); }
               ^
Fast-DDS-2.9.0/src/cpp/utils/shared_memory/RobustInterprocessCondition.hpp:372:45: note: in instantiation of function template specialization 'boost::interprocess::interprocess_semaphore::timed_wait<boost::date_time::special_values>' requested here
            semaphores_pool_[sem_index].sem.timed_wait(boost::posix_time::pos_infin);
                                            ^
boost/interprocess/sync/posix/timepoint_to_timespec.hpp:50:17: note: candidate function not viable: no known conversion from 'const boost::date_time::special_values' to 'const boost::interprocess::ipcdetail::ustime' for 1st argument
inline timespec timepoint_to_timespec (const ustime &tm)
                ^
boost/interprocess/sync/posix/timepoint_to_timespec.hpp:33:17: note: candidate template ignored: substitution failure [with TimePoint = boost::date_time::special_values]: no type named 'type' in 'boost::interprocess::ipcdetail::enable_if_ptime<boost::date_time::special_values>'
inline timespec timepoint_to_timespec ( const TimePoint &tm
                ^
boost/interprocess/sync/posix/timepoint_to_timespec.hpp:59:17: note: candidate template ignored: substitution failure [with TimePoint = boost::date_time::special_values]: no type named 'type' in 'boost::interprocess::ipcdetail::enable_if_time_point<boost::date_time::special_values>'
inline timespec timepoint_to_timespec ( const TimePoint &tm
                ^

I attempted to add a repro case. What would be the best way to approach a fix? Thanks!

Support for pos_inf was not intended in the library (it was not even tested), but it seems that posix_ptime has a converting constructor for pos_inf and the trick worked. When the interface was templated to support different time libraries (std, boost, date_time), then the converting constructor does not kick in. Adding support for pos_inf and friends would make again Interprocess dependent on date-time which, something that we want to avoid. I've tried some workarounds but the solution does not seem plausible or at least easy. So I'm afraid that support for pos_inf was lost in the transition creating an unintended breaking change...

Strangely, Fast-DDS is using a timed function with the infinite timeout to implement a blocking lock. I can suggest changing

semaphores_pool_[sem_index].sem.timed_wait(boost::posix_time::pos_infin);

with

semaphores_pool_[sem_index].sem.timed_wait(boost::posix_time::ptime(boost::posix_time::pos_infin));

that should work with all versions of Boost.Interprocess

boostorg / interprocess

add positive infinity test case #197