[Bug c++/58929] New: condition_variable does not wait without -pthread

[lundberj at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58929

            Bug ID: 58929
           Summary: condition_variable does not wait without -pthread
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: lundberj at gmail dot com

A warning would have been helpful for this case of missed -pthread. 
Normally a runtime error is at least generated but the following C++11 code
compiles fine with all warnings enabled, and also executes without run time
errors, but does so incorrectly if -pthread is not given. (wait_for is then
just skipped). 

cheers Johan.

#include <chrono>
#include <mutex>
#include <condition_variable>
void sleep10(){ // sleeps only of -pthread is used
  std::mutex m;
  std::condition_variable cv;
  std::unique_lock<std::mutex> lk(m);
  cv.wait_for(lk,std::chrono::seconds{10}); 
}