diff options
Diffstat (limited to 'build2/test/script/regex.cxx')
| -rw-r--r-- | build2/test/script/regex.cxx | 35 |
1 files changed, 33 insertions, 2 deletions
diff --git a/build2/test/script/regex.cxx b/build2/test/script/regex.cxx index 6b15266..bbd1738 100644 --- a/build2/test/script/regex.cxx +++ b/build2/test/script/regex.cxx @@ -2,6 +2,8 @@ // copyright : Copyright (c) 2014-2019 Code Synthesis Ltd // license : MIT; see accompanying LICENSE file +#include <locale> + #include <build2/test/script/regex.hxx> using namespace std; @@ -163,11 +165,40 @@ namespace build2 // line_char_locale // + + // An exemplar locale with the std::ctype<line_char> facet. It is + // used for the subsequent line char locale objects creation (see + // below) which normally ends up with a shallow copy of a reference- + // counted object. + // + // Note that creating the line char locales from the exemplar is not + // merely an optimization: there is a data race in the libstdc++ (at + // least as of GCC 9.1) implementation of the locale(const locale&, + // Facet*) constructor (bug #91057). + // + // Also note that we install the facet in init() rather than during + // the object creation to avoid a race with the std::locale-related + // global variables initialization. + // + static locale line_char_locale_exemplar; + + void + init () + { + line_char_locale_exemplar = + locale (locale (), + new std::ctype<line_char> ()); // Hidden by ctype bitmask. + } + line_char_locale:: line_char_locale () - : locale (locale (), - new std::ctype<line_char> ()) // Hidden by ctype bitmask. + : locale (line_char_locale_exemplar) { + // Make sure init() has been called. + // + // Note: has_facet() is hidden by a private function in libc++. + // + assert (std::has_facet<std::ctype<line_char>> (*this)); } // char_regex |