| Home | Libraries | People | FAQ | More

### Thread Safety

The Boost.Regex library is thread safe when Boost is: you can verify that Boost is in thread safe mode by checking to see if `BOOST_HAS_THREADS` is defined: this macro is set automatically by the config system when threading support is turned on in your compiler.

Class `basic_regex` and its typedefs regex and wregex are thread safe, in that compiled regular expressions can safely be shared between threads. The matching algorithms `regex_match`, `regex_search`, and `regex_replace` are all re-entrant and thread safe. Class `match_results` is now thread safe, in that the results of a match can be safely copied from one thread to another (for example one thread may find matches and push `match_results` instances onto a queue, while another thread pops them off the other end), otherwise use a separate instance of `match_results` per thread.

The POSIX API functions are all re-entrant and thread safe, regular expressions compiled with regcomp can also be shared between threads.

Finally note that changing the global locale invalidates all compiled regular expressions, therefore calling `set_locale` from one thread while another uses regular expressions will produce unpredictable results.

There is also a requirement that there is only one thread executing prior to the start of main().