Quick Answer: Are STL data structures thread safe?

Are STL thread-safe?

The SGI implementation of STL is thread-safe only in the sense that simultaneous accesses to distinct containers are safe, and simultaneous read accesses to to shared containers are safe.

Is STL vector thread-safe?

Well, vector’s interface isn’t optimal for concurrent use. It is fine if the client has access to a lock, but for for the interface to abstract locking for each operation — no. In fact, vector’s interface cannot guarantee thread safety without an external lock (assuming you need operations which also mutate).

Are C++ containers thread-safe?

He asked for facts: “Do C++11 versions of STL containers have some level of thread safety guaranteed?” The factual answer is “Yes,” because the standard does have some level of guarantees.

Is cout thread-safe?

A side note: std::cout is thread-safe

The C++11 standard guarantees, that you must not protect the single characters, written to std::cout. Each character will atomically be written.

Is a C++ vector thread-safe?

The C++11 standard does not expect to be able to safely call non const functions simultaneously. Therefore all classes available from the standard, e.g. std::vector<>, can safely be accessed from multiple threads in the same manner.

Why are vectors thread-safe?

Vector is a thread-safe collection – all its methods are synchronized by default. This is why it’s recommended to use ArrayList instead – it’s not thread-safe which results in a better performance for single-thread applications.

Is std :: sort thread-safe?

std::sort could, in principle, use parallel execution when sorting elements of fundamental type (it wouldn’t be observable whether it does), but not user-defined type (unless explicitly given permission via execution policy parameter, of course). The type’s operator< may not be thread-safe.

What does STL stand for C++?

STL stands for Standard Template Library. If you’ve used C++ even in small projects, you’ve likely already used STL – which is a great thing! Using STL in C++ makes your code more expressive, simple, and easy to understand.

What is containers in STL?

An STL container is a collection of objects of the same type (the elements). Container owns the elements. Creation and destruction is controlled by the container.

Is unordered_map find thread safe?

std::unordered_map is a good fit for some multi-threaded situations. There are also other concurrent maps from Intel TBB: tbb:concurrent_hash_map . It supports fine-grained, per-key locking for insert/update, which is something that few other hashmaps can offer.

Is read thread-safe?

Roughly speaking, a function is thread safe if invoking it concurrently produces sane results, equivalent to those you get when you invoke it non-concurrently. If a single thread calling read never processes the same data twice, then read is thread safe if two threads calling it also never process the same data twice.

How you can make program thread-safe?

There are basically four ways to make variable access safe in shared-memory concurrency:

1. Confinement. Don’t share the variable between threads. …
2. Immutability. Make the shared data immutable. …
3. Threadsafe data type. …
4. Synchronization.

Is std :: CERR thread-safe?

Insertion to and extraction from global stream objects ( std::cout, std::cin, std::cerr , and std::clog ) is thread-safe. To put it more formally: writing to std::cout is not participating in a data race, but does create a race condition. This means that the output depends on the interleaving of threads.