c++ - Invalid null pointer error when converting std::chrono::system_clock::time_point::min() to string -

i following example in nicolai m. josuttis' "the c++ standard library (second edition)", page 152-153, details example print epoch, current time, minimum , maximum times of std::chrono::system_clock introduced in c++11.

i using microsoft visual studio 2012, , assertion triggered in <xstring>, due invalid null pointer. occurs on line std::string ts = std::ctime( &t ) in code below after setting tp = std::chrono::system_clock::time_point::min();

#include <chrono> #include <ctime> #include <string> #include <iostream>  std::string asstring( const std::chrono::system_clock::time_point& tp ) {     std::time_t t = std::chrono::system_clock::to_time_t( tp );     std::string ts = std::ctime( &t );     ts.resize( ts.size()-1 );     return ts; }  int main() {     std::chrono::system_clock::time_point tp;     std::cout << "epoch: " << asstring(tp) << std::endl;      tp = std::chrono::system_clock::now();     std::cout << "now: " << asstring(tp) << std::endl;      tp = std::chrono::system_clock::time_point::min();     std::cout << "min: " << asstring(tp) << std::endl;      tp = std::chrono::system_clock::time_point::max();     std::cout << "max: " << asstring(tp) << std::endl;      return 0; } 

is due implementation error dinkumware in <chrono> library, or typo/mistake in book? have gone on code given in book again , again see if have copied out incorrectly, not appear case. i'd grateful insights given.

it looks std::ctime returns null, indicates incorrect t value. because call asstring uses value of time_point cannot represented in time_t type.