1 files changed, 46 insertions, 1 deletions
diff --git a/libstdc++-v3/src/c++11/regex.cc b/libstdc++-v3/src/c++11/regex.cc
index 0a4a5524b22..d5e1cc7612a 100644
--- a/libstdc++-v3/src/c++11/regex.cc
+++ b/libstdc++-v3/src/c++11/regex.cc
@@ -35,8 +35,53 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 		      __attribute__((unused)))
   { _GLIBCXX_THROW_OR_ABORT(regex_error(__ecode)); }
 
+namespace
+{
+  const char*
+  desc(regex_constants::error_type e)
+  {
+    using namespace regex_constants;
+    switch (e)
+    {
+    case error_collate:
+      return "Invalid collating element in regular expression";
+    case error_ctype:
+      return "Invalid character class in regular expression";
+    case error_escape:
+      return "Invalid escape in regular expression";
+    case error_backref:
+      return "Invalid back reference in regular expression";
+    case error_brack:
+      return "Mismatched '[' and ']' in regular expression";
+    case error_paren:
+      return "Mismatched '(' and ')' in regular expression";
+    case error_brace:
+      return "Mismatched '{' and '}' in regular expression";
+    case error_badbrace:
+      return "Invalid range in '{}' in regular expression";
+    case error_range:
+      return "Invalid character range in regular expression";
+    case error_space:
+      return "Insufficient memory to compile regular expression";
+    case error_badrepeat:
+      return "Invalid '?', '*', or '+' in regular expression";
+    case error_complexity:
+      return "Complexity of regex match exceeded implementation limits";
+    case error_stack:
+      return "Insufficient memory to determine regex match";
+    case _S_null:
+      return "Unexpected null character in regular expression";
+    case _S_grammar:
+      return "Conflicting regex grammar options";
+    default:
+      return "regex error";
+    };
+
+  }
+}
+
   regex_error::regex_error(regex_constants::error_type __ecode)
-  : std::runtime_error("regex_error"), _M_code(__ecode)
+  : std::runtime_error(desc(__ecode)), _M_code(__ecode)
   { }
 
   regex_error::~regex_error() throw() { }