Is possible to use std::deque::push_back() and std::deque::front()/std::deque::pop_front() on different threads without synchronization? [duplicate]

Answer 1

If you are not synchronizing between readers and writers, there is a possibility of data corruption.

So the answer in general is NO.

To requote

Multiple readers are safe. Multiple threads may simultaneously read the contents of a single container, and this will work correctly. Naturally, there must not be any writers acting on the container during the reads.

Depending on the environment, you can use different concurrent containers. For example, MSDN supports concurrent queue And there are boost libraries which provides lock free containers as well.

Answer 2

Generally, no, your code is not thread-safe.

See relevant documentation for MSVC ("Thread Safety in the C++ Standard Library"):

If a single object is being written to by one thread, then all reads and writes to that object on the same or other threads must be protected. For example, given an object A, if thread 1 is writing to A, then thread 2 must be prevented from reading from or writing to A.

Or for GCC ("Concurrency > Containers")

[...] locking must nearly always be done outside the container, by client code (that'd be you, not us).

The C++ standard (even the C++11 one) does not mandate thread-safe access here. If you use some other compiler, its documentation will surely tell you something similar about concurrent access to container classes.