1[/
2  Copyright 2006-2007 John Maddock.
3  Distributed under the Boost Software License, Version 1.0.
4  (See accompanying file LICENSE_1_0.txt or copy at
5  http://www.boost.org/LICENSE_1_0.txt).
6]
7
8
9[section:thread_safety Thread Safety]
10
11The Boost.Regex library is thread safe when Boost is: you can verify that
12Boost is in thread safe mode by checking to see if `BOOST_HAS_THREADS` is
13defined: this macro is set automatically by the config system when
14threading support is turned on in your compiler.
15
16Class [basic_regex] and its typedefs regex and wregex are thread safe,
17in that compiled regular expressions can safely be shared between threads.
18The matching algorithms [regex_match], [regex_search], and [regex_replace]
19are all re-entrant and thread safe. Class [match_results] is now thread safe,
20in that the results of a match can be safely copied from one thread to
21another (for example one thread may find matches and push [match_results]
22instances onto a queue, while another thread pops them off the other end),
23otherwise use a separate instance of [match_results] per thread.
24
25The [link boost_regex.ref.posix POSIX API functions] are all re-entrant and thread safe, regular
26expressions compiled with regcomp can also be shared between threads.
27
28The [link boost_regex.ref.deprecated.old_regex class RegEx] is
29only thread safe if each thread gets its own
30RegEx instance (apartment threading) - this is a consequence of
31RegEx handling both compiling and matching regular expressions.
32
33Finally note that changing the global locale invalidates all compiled
34regular expressions, therefore calling `set_locale` from one thread
35while another uses regular expressions will produce unpredictable results.
36
37There is also a requirement that there is only one thread executing prior
38to the start of main().
39
40[endsect]
41
42