use working source_location

GaudiPluginService/include/Gaudi/PluginServiceV2.h

@@ -23,24 +23,56 @@
 #include <type_traits>
 #include <typeinfo>
 #include <utility>
+#include <cstdint>
 
 #if __cplusplus > 201703L && __has_include( <source_location> )
 #  include <source_location>
 namespace Gaudi::PluginService::Details {
   using std::source_location;
 }
-#elif __cplusplus >= 201402L && __has_include( <experimental/source_location> ) && false
+
+#elif __cplusplus >= 201402L && __has_include( <experimental/source_location> ) && false //TODO: false for debugging, turn on again
 #  include <experimental/source_location>
 namespace Gaudi::PluginService::Details {
   using std::experimental::source_location;
 }
 #else
 namespace Gaudi::PluginService::Details {
-  struct source_location {
-    std::string file_name() {return "";};
-    std::string line() {return "";}
-    static constexpr source_location current() { return source_location();}
-  };
+
+struct source_location {
+
+  // 14.1.2, source_location creation
+  static constexpr source_location
+  current(const char* __file = __builtin_FILE(),
+    const char* __func = __builtin_FUNCTION(),
+    int __line = __builtin_LINE(),
+    int __col = 0) noexcept
+  {
+    source_location __loc;
+    __loc._M_file = __file;
+    __loc._M_func = __func;
+    __loc._M_line = __line;
+    __loc._M_col = __col;
+    return __loc;
+  }   
+
+  constexpr source_location() noexcept
+  : _M_file("unknown"), _M_func(_M_file), _M_line(0), _M_col(0)
+  { } 
+
+  // 14.1.3, source_location field access
+  constexpr uint_least32_t line() const noexcept { return _M_line; }
+  constexpr uint_least32_t column() const noexcept { return _M_col; }
+  constexpr const char* file_name() const noexcept { return _M_file; }
+  constexpr const char* function_name() const noexcept { return _M_func; }
+
+private:
+  const char* _M_file;
+  const char* _M_func;
+  uint_least32_t _M_line;
+  uint_least32_t _M_col;
+};  
+
 }
 #endif