Reports whether OESystem memory allocation uses thread-safe mutual exclusion to access its data structures. By default, this value is true. This allows OEChem molecules and other toolkit objects to be allocated and deallocated simultaneously in concurrent operating system threads. However, for applications that only have a single thread of execution, the use of thread-safe memory allocation can cause a small performance overhead on some platforms. Setting this value to false, using the OESetThreadSafe function can be used to instruct OESystem (and the toolkits built upon it) to use faster implementations when it is known to be safe.