The library is fully thread safe and re-entrant provided the function and class templates in the library are instantiated with built-in floating point types: i.e. the types float, double and long double.

However, the library is not thread safe when used with user-defined (i.e. class type) numeric types.

The reason for the latter limitation is the need to initialise symbolic constants using constructs such as:

static const T coefficient_array = { ... list of values ... };

Which is always thread safe when T is a built-in floating point type, but not when T is a user defined type: as in this case there is a need for T's constructors to be run, leading to potential race conditions.

This limitation may be addressed in a future release.