Merge pull request #6712 from bangerth/regex

Fix a regex.

Author: tjhei

source/main.cc

@@ -75,6 +75,17 @@ namespace
   {
     std::string return_value;
 
+    // Declare the regex we would like to match against each line of the
+    // input file. Make sure we have a \r at the very end because the '.'
+    // operator matches every printable character but not special ones
+    // like \r. As a consequence, a line that ends in a Windows-style
+    // \r would not match this regex even if it sets the correct parameter.
+    //
+    // We will deal with the presence of Windows line endings on Unix systems
+    // in the places where we call this function, and so include the \r
+    // in the second match group.
+    const std::regex regex ("set[ \t]+" + parameter_name + "[ \t]*=[ \t]*(.*\r?)");
+
     std::istringstream x_file(parameters);
     while (x_file)
       {
@@ -91,7 +102,6 @@ namespace
           line.erase(line.size() - 1, std::string::npos);
 
         std::match_results<std::string::const_iterator> matches;
-        const std::regex regex ("set[ \t]+" + parameter_name + "[ \t]*=[ \t]*(.*)");
         if (std::regex_match(line, matches, regex))
           {
             // Since the line as a whole matched, the 'matches' variable needs to