Thread safety of Matlab engine API

Question

I have discovered through trial and error that the MATLAB engine function is not completely thread safe.

Does anyone know the rules?

Discovered through trial

Answer 1

When I first started using the engine, I didn't run across any documentation on thread safety, so I assumed that it was not thread-safe.

I use a C++ class to synchronize access to an engine instance. For more parallel processing designs, I instantiate multiple instances of the engine class.

(edit) I'm using MATLAB R14 on Solaris. I open the engine using the 'engOpen' call, and close it using 'engClose'. My platform does not crash when the Close is called by a different thread than the one that called Open.

Answer 2

From the documentation,

MATLAB libraries are not thread-safe. If you create multithreaded applications, make sure only one thread accesses the engine application.

Answer 3

You can use engOpenSingleUse instead of using engOpen to make more than one thread working separately. (Only Windows)

Answer 4

From a user's perspective, Matlab's interpreter is purely single-threaded. To be safe, you probably need to make all access to the engine from a single thread.

Note that internally, Matlab uses plenty of threads. There are GUI threads, and in the last few versions, the interpreter can use multiple threads behind the scenes. But, the interpreter is semantically equivalent to a single-threaded interpreter (with interrupts).