Declare variable to be used with chrono lib inside a class

Question

0.00/5 (No votes)

See more:

I made a class that uses a timer.
The problem is that I cacnot assign "auto" to start/stop so I need the return data type to assign it to start and stop.

Is there a way to use auto using static or similar that allows #include <chrono> in the .cpp part only?

What I have tried:

class c_clase
{
public:
	void timer(char *title=0,int data_size=1){    	stop_time= chrono::system_clock::now();double us=(double) chrono::duration_cast<chrono::microseconds>(stop_time - start_time).count();	if (title) printf("%s time = %7lgms = %7lg MOPs\n",title,(double) us*1e-3, (double)data_size/us); start_time= chrono::system_clock::now(); }
private:
	std::chrono::time_point<std::chrono::system_clock> start_time,stop_time;
};

Posted 8-Oct-17 23:31pm

Javier Luis Lopez

Updated 9-Oct-17 20:38pm

v6

Add a Solution

2 solutions

Solution 2

Quote:
Also tried:
std::chrono::time_point<std::chrono::system_clock> start_time,stop_time;
But link errors appeared

What errors did you get? I tried it. It compiles fine (once null_char was removed from the code).

Posted 9-Oct-17 0:06am

CPallini

Comments

Javier Luis Lopez 9-Oct-17 6:26am

It was due #include <chrono> was not added to the .hpp code because I try write includes in the .cpp only or in a more complex project as in the following way:
https://photos.google.com/photo/AF1QipOtS9iHdhEHSJPpKOKrvy6X6ukVN2rETHklez1b

Thanks, at least I removed null_char; at the code

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Jochen Arndt · Accepted Answer · 2017-10-08T23:49:00

Solution 1

The type is std::chrono::system_clock::time_point.

Posted 8-Oct-17 23:49pm

Jochen Arndt

Comments

Javier Luis Lopez 9-Oct-17 5:58am

Thank you, I updated it but using
std::chrono::time_point<std::chrono::system_clock> if not errors appeared

Jochen Arndt 9-Oct-17 6:27am

I have tested it meanwhile with the

std::chrono::time_point<std::chrono::system_clock>

type and it works here (like also mentioned by CPallini).

" Is there a way to use auto using static or similar that allows #include <chrono> in the .cpp part only?"

No. Auto requires an initializer. While it is possible to have a static auto class member variable the requirement of the initializer implies that the variable must be const.