CODEWITHSUNDEEP
c++c++11g++c++-chrono
user1950349
user1950349

Reputation: 5146

error: uint64_t was not declared in this scope when compiling C++ program

I am trying out a simple program to print the timestamp value of steady_clock as shown below:

#include <iostream>
#include <chrono>
using namespace std;
int main ()
{
  cout << "Hello World! ";
  uint64_t now = duration_cast<milliseconds>(steady_clock::now().time_since_epoch()).count();
  cout<<"Value: " << now << endl;
  
  return 0;
}

But whenever I am compiling like this g++ -o abc abc.cpp, I am always getting an error:

    In file included from /usr/include/c++/4.6/chrono:35:0,
                     from abc.cpp:2:
    /usr/include/c++/4.6/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the upcoming ISO C++ standard, C++0x. This support is currently experimental, and must be enabled with the -std=c++0x or -std=gnu++0x compiler options.
    abc.cpp: In function âint main()â:
    abc.cpp:7:3: error: âuint64_tâ was not declared in this scope
    abc.cpp:7:12: error: expected â;â before ânowâ
    abc.cpp:8:22: error: ânowâ was not declared in this scope

Is there anything wrong I am doing?

Upvotes: 15

Views: 30684

Answers (3)

liu bluse
liu bluse

Reputation: 167

If you really want to include, add "#define __STDC_LIMIT_MACROS"

Ref: https://stackoverflow.com/a/3233069/6728794

Upvotes: -1

Arun
Arun

Reputation: 2102

Obviously, I'm not following certain best practices, but just trying to get things working for you

#include <iostream>
#include <chrono>
#include <cstdint> // include this header for uint64_t

using namespace std;
int main ()
{
  {
    using namespace std::chrono; // make symbols under std::chrono visible inside this code block
    cout << "Hello World! ";
    uint64_t now = duration_cast<milliseconds>(steady_clock::now().time_since_epoch()).count();
    cout<<"Value: " << now << endl;
  }

  return 0;
}

and then compile using C++11 enabled (c++0x in your case)

g++ -std=c++0x -o abc abc.cpp

Upvotes: 15

JerryYoung
JerryYoung

Reputation: 277

You should include stdint.h file.

Upvotes: 7

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