boost::split will change the input string when the input string is not const?

The parameters of boost::split function is not constant. when the input string of split is not constant, boost::split will change the input string or move the input string into another memory address?

The background of question: my service is write by C++, it's always core dump. I have trying to find the reason. my code used boost::split function, and given a no-constant reference of string to boost::split. this code will run multithreaded, so i think it's not tread safety and result in core dump.