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std thread,mutex,cv and static linking with GCC
- From: Damian Lezama <Damian dot Lezama at riverbed dot com>
- To: "libstdc++ at gcc dot gnu dot org" <libstdc++ at gcc dot gnu dot org>
- Date: Wed, 22 Oct 2014 15:40:38 +0000
- Subject: std thread,mutex,cv and static linking with GCC
- Authentication-results: sourceware.org; auth=none
I was getting random crashes when using thread, mutex, and cv and statically linking my project. Some of the libraries I link against use pthread, so I narrowed the issue down to this test:
I statically link a simple test that uses thread, mutex, and cv like this: "g++ --std=c++11 -pthread -static test.cc" and I get this when I run it:
terminate called after throwing an instance of 'std::system_error'
what(): Enable multithreading to use std::thread: Operation not permitted
Everything works fine if I don't use -static, the problem is specific to static linking. If in my test I use pthread directly to create a thread, then it runs and creating an std::thread also works, but the test crashes when using the cv. My theory is that the linker is being lazy (weak references? optimization?) and the pthread stuff std needs is not included in the binary unless referenced somewhere else. In real projects this is quite dangerous because having dependencies that use most of the pthread stuff makes these crashes rare (I caught this problem with a stress test).
Any ideas? Is this s bug in the library?