Made todo_guard more prominent, we have no finally

tap++/doc/libtap++.pod

@@ -193,9 +193,11 @@ given I<reason>.  Note that you have to do the skipping yourself.
 
 =item B<TODO>
 
+  {
+  todo_guard why;
   TODO="why"
   my_tests_here ...
-  TODO=""
+  }
 
 C<TODO> is a global string variable that tells TAP harness the reason
 the current test is expected to fail.  You set TODO before a block of
@@ -214,8 +216,9 @@ Note that TODO manipulates a global variable.  Thus, you should be
 careful to set it to "" before going to another section of the
 program.  An easy mistake to make is to have a failing section of code
 that throws an exception, taking you out of the current scope without
-resetting TODO.  Adding a try...finally block around such code fixes
-the problem.
+resetting TODO. To make it easier to deal with this in a thread-safe
+manner, the todo_guard class is provided. Objects of this class will
+reset TODO when they fall out of scope.
 
 =back
 

tap++/headers/tap++.h

@@ -195,6 +195,13 @@ namespace TAP {
 	}
 
 	extern std::string TODO; 
+
+	class todo_guard {
+		const std::string value;
+		public:
+		todo_guard() throw();
+		~todo_guard() throw();
+	};
 }
 
 #ifdef WANT_TEST_EXTRAS
@@ -215,12 +222,6 @@ namespace TAP {
 		void start_block(unsigned) throw();
 		unsigned stop_block() throw(fatal_exception);
 
-		class todo_guard {
-			const std::string value;
-			public:
-			todo_guard() throw();
-			~todo_guard() throw();
-		};
 	}
 
 	void skip(const std::string& reason) throw(details::Skip_exception);

tap++/source/tap++.C

@@ -158,6 +158,11 @@ namespace TAP {
 		}
 		details::error = &new_error;
 	}
+	todo_guard::todo_guard() throw() : value(TODO) {
+	}
+	todo_guard::~todo_guard() throw() {
+		TODO = value;
+	}
 	namespace details {
 		std::ostream* output = &std::cout;
 		std::ostream* error = &std::cout;
@@ -171,12 +176,7 @@ namespace TAP {
 			return ret;
 		}
 
-		todo_guard::todo_guard() throw() : value(TODO) {
-		}
-		todo_guard::~todo_guard() throw() {
-			TODO = value;
-		}
-	 	char const * failed_test_msg(){
+	 	char const * failed_test_msg() throw() {
 		     return is_todo_test()?"Failed (TODO) test":"Failed test";
 		}