TApplication::Run() stucks the terminal

Newbie
1

ROOT Version: 6.22
_Platform: ubuntu
_Compiler: g++

Hi,
I have a code in c++ where I use TApplication to stop terminating the program before the graph Shows.
the code:

#include <iostream>
#include "TF1.h"
#include "TApplication.h"
using namespace std;
int main()
{
    TApplication app("app", nullptr, nullptr);
    TF1 *f1 = new TF1("f1","sin(x)", -5, 5);
    f1->SetLineColor(kBlue+1);
    f1->SetTitle("My graph; x");
    f1->Draw();
    app.Run();
    return 0;
}

It perfectly runs, but the terminal stucks before the program returns 0
How could I solve this??
Thank you,
Regards.

2

Hello,

Is your goal to plot the function and inspect it interactively? If that’s the case, it might be better that you draw your function from the ROOT prompt.

$ root
root [0] TF1 *f1 = new TF1("f1","sin(x)", -5, 5);
root [1] f1->SetLineColor(kBlue+1);
root [2] f1->SetTitle("My graph; x");
root [3] f1->Draw();
1 Like
3

Also, if a compiled version is a requirement for you, you could do the following:

#include "TF1.h"
#include "TApplication.h"
#include "TCanvas.h"
using namespace std;
int main()
{
        TApplication app("app", nullptr, nullptr);
        TCanvas* c = new TCanvas("c", "Something", 0, 0, 800, 600);
        TF1 *f1 = new TF1("f1","sin(x)", -5, 5);
        f1->SetLineColor(kBlue+1);
        f1->SetTitle("My graph; x");
        f1->Draw();
        c->Modified(); c->Update();
        printf("Type any digit and hit `Enter` to exit: "); Int_t a; std::cin>>a;
        return 0;
}
1 Like
5

Sir, I require to run the program by g++ compiler

6

Hello, sir basically you are holding the program by putting input request. Yes I can use that. But is there any other way to hold the program on untill I close the graph canvas, using TApplocation??
By the way thank you sir, it works.

7

Perhaps @bellenot or @couet know?

8

If you want to quit the application when closing the canvas:

#include <iostream>
#include "TF1.h"
#include "TApplication.h"
#include "TCanvas.h"
#include "TRootCanvas.h"

int main()
{
    TApplication app("app", nullptr, nullptr);
    TCanvas* c = new TCanvas("c", "Something", 0, 0, 800, 600);
    TF1 *f1 = new TF1("f1","sin(x)", -5, 5);
    f1->SetLineColor(kBlue+1);
    f1->SetTitle("My graph; x");
    f1->Draw();
    c->Modified(); c->Update();
    TRootCanvas *rc = (TRootCanvas *)c->GetCanvasImp();
    rc->Connect("CloseWindow()", "TApplication", gApplication, "Terminate()");
    app.Run();
    return 0;
}
9

And if you just want the ROOT prompt:

#include <iostream>
#include "TF1.h"
#include "TRint.h"
#include "TCanvas.h"

int main()
{
    TRint app("app", nullptr, nullptr);
    TCanvas* c = new TCanvas("c", "Something", 0, 0, 800, 600);
    TF1 *f1 = new TF1("f1","sin(x)", -5, 5);
    f1->SetLineColor(kBlue+1);
    f1->SetTitle("My graph; x");
    f1->Draw();
    c->Modified(); c->Update();
    app.Run();
    return 0;
}