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| 4 | <title>Boost.Regex: Thread Safety</title> |
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| 8 | <body> |
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| 9 | <P> |
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| 11 | <TR> |
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| 12 | <td valign="top" width="300"> |
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| 13 | <h3><a href="../../../index.htm"><img height="86" width="277" alt="C++ Boost" src="../../../boost.png" border="0"></a></h3> |
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| 14 | </td> |
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| 15 | <TD width="353"> |
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| 16 | <H1 align="center">Boost.Regex</H1> |
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| 17 | <H2 align="center">Thread Safety</H2> |
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| 18 | </TD> |
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| 19 | <td width="50"> |
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| 20 | <h3><a href="index.html"><img height="45" width="43" alt="Boost.Regex Index" src="uarrow.gif" border="0"></a></h3> |
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| 23 | </TABLE> |
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| 24 | </P> |
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| 25 | <HR> |
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| 26 | <P>The regex library is thread safe when Boost is: you can verify that Boost is in |
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| 27 | thread safe mode by checking to see if BOOST_HAS_THREADS is defined: this macro |
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| 28 | is set automatically by the config system when threading support is turned on |
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| 29 | in your compiler. |
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| 30 | </P> |
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| 31 | <P>Class <A href="basic_regex.html">basic_regex</A><> and its typedefs regex |
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| 32 | and wregex are thread safe, in that compiled regular expressions can safely be |
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| 33 | shared between threads. The matching algorithms <A href="regex_match.html">regex_match</A>, |
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| 34 | <A href="regex_search.html">regex_search</A>, <A href="regex_grep.html">regex_grep</A>, |
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| 35 | <A href="regex_format.html">regex_format</A> and <A href="regex_merge.html">regex_merge</A> |
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| 36 | are all re-entrant and thread safe. Class <A href="match_results.html">match_results</A> |
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| 37 | is now thread safe, in that the results of a match can be safely copied from |
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| 38 | one thread to another (for example one thread may find matches and push |
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| 39 | match_results instances onto a queue, while another thread pops them off the |
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| 40 | other end), otherwise use a separate instance of <A href="match_results.html">match_results</A> |
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| 41 | per thread. |
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| 42 | </P> |
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| 43 | <P>The <A href="posix_api.html">POSIX API functions</A> are all re-entrant and |
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| 44 | thread safe, regular expressions compiled with <I>regcomp</I> can also be |
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| 45 | shared between threads. |
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| 46 | </P> |
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| 47 | <P>The class<A href="regex.html"> RegEx</A> is only thread safe if each thread |
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| 48 | gets its own RegEx instance (apartment threading) - this is a consequence of |
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| 49 | RegEx handling both compiling and matching regular expressions. |
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| 50 | </P> |
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| 51 | <P>Finally note that changing the global locale invalidates all compiled regular |
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| 52 | expressions, therefore calling <I>set_locale</I> from one thread while another |
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| 53 | uses regular expressions <I>will</I> produce unpredictable results. |
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| 54 | </P> |
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| 55 | <P> |
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| 56 | There is also a requirement that there is only one thread executing prior to |
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| 57 | the start of main().</P> |
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| 58 | <HR> |
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| 59 | <p>Revised |
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| 60 | <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan --> |
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| 61 | 24 Oct 2003 |
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| 62 | <!--webbot bot="Timestamp" endspan i-checksum="39359" --></p> |
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| 63 | <p><i>© Copyright John Maddock 1998- |
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| 64 | <!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%Y" startspan --> |
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| 65 | 2003<!--webbot bot="Timestamp" endspan i-checksum="39359" --></i></p> |
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| 66 | <P><I>Use, modification and distribution are subject to the Boost Software License, |
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| 67 | Version 1.0. (See accompanying file <A href="../../../LICENSE_1_0.txt">LICENSE_1_0.txt</A> |
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| 68 | or copy at <A href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</A>)</I></P> |
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| 69 | </body> |
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| 70 | </html> |
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