Defines the macros traditionally defined in the Standard C Library header <time.h>.
#if <TRADITIONAL C HEADERS>
   #include <time.h>
namespace std {
   using ::asctime; 
   using ::clock; 
   using ::clock_t; 
   using ::ctime;
   using ::difftime; 
   using ::gmtime; 
   using ::localtime;
   using ::mktime; 
   using ::size_t;
   using ::strftime; 
   using ::time;
   using ::time_t; 
   using ::tm;
}
#endif
Remarks
Including this header also ensures that the names declared with external linkage in the Standard C Library header are declared in the std namespace. In this implementation, the names may or may not also be declared in the global namespace, depending on the specific translation environment.