Fl_Scroll broken?

[supsm17]

I made an application which adds check buttons for each entry found in a directory (this part isn't super important). I've noticed that the text on the check buttons don't match what I get when I cout the string. 

This is what it is supposed to say v

Also, I've noticed that when I get the utf8 string (.u8string()) of a filesystem path, then scroll away and scroll back, the text changes to garbage. The garbage changes every time I restart my program. 

This does not happen when I get a regular string (.string())

The scroll bar also does not show up until I start scrolling (as seen in the first screenshot)


Code:

for (auto& entry : std::filesystem::directory_iterator(std::filesystem::u8path(path)))

{

addentry(entry.path().filename().u8string());

std::cout << entry.path().filename().u8string() << std::endl;

Fl::wait();
}

void addentry(std::string name)

{

ui->scroll->begin();

Fl_Check_Button* o = new Fl_Check_Button(470, 60 + 15 * numbuttons, 1000, 15, name.c_str());

o->down_box(FL_DOWN_BOX);

o->value(1);

o->user_data((void*)(numbuttons));

o->callback((Fl_Callback*)(callback));

o->when(FL_WHEN_CHANGED);

ui->scroll->end();

numbuttons++;

}

UI is defined as
extern UI* ui = new UI()

UI class:

h file: 

// generated by Fast Light User Interface Designer (fluid) version 1.0306

#ifndef fltktest_h

#define fltktest_h

#include <FL/Fl.H>

#include <FL/Fl_Window.H>

#include <FL/Fl_Button.H>

extern void run(Fl_Button*, void*);

#include <FL/Fl_Text_Display.H>

#include <FL/Fl_Check_Button.H>

extern void conversion(Fl_Check_Button*, void*);

#include <FL/Fl_Scroll.H>

class UI {

public:

  UI();

  Fl_Window *window;

  Fl_Text_Display *text_display;

  Fl_Scroll *scroll;

  void show();

};

#endif

cxx file:

// generated by Fast Light User Interface Designer (fluid) version 1.0306

#include "fltktest.h"

UI::UI() {

  { window = new Fl_Window(659, 349, "FLTK test");

    window->user_data((void*)(this));

    // removed irrelevant stuff

    { scroll = new Fl_Scroll(445, 40, 190, 260, "Title");

      { // padding

        Fl_Check_Button* o = new Fl_Check_Button(470, 45, 150, 15);

        o->down_box(FL_DOWN_BOX);

        o->labeltype(FL_NO_LABEL);

        o->hide();

        o->deactivate();

      } // Fl_Check_Button* o

      scroll->end();

    } // Fl_Scroll* scroll

    window->end();

  } // Fl_Window* window

}

void UI::show() {

  window->show();

}

Any help is appreciated :)

[Greg Ercolano]

Fl_Check_Button* o = new Fl_Check_Button(470, 60 + 15 * numbuttons, 1000, 15, name.c_str());

    Here Fl_Check_Button's constructor is saving the pointer to name.c_str()
    and is not making a copy of the string. So the string has gone out of scope by the
    time the strings are being drawn.

    Instead use:

Fl_Check_Button* o = new Fl_Check_Button(470, 60 + 15 * numbuttons, 1000, 15);
        o->copy_label(name.c_str());

    ..so that the widget internally makes a copy of the string.

[supsm17]

That solved the issue, thank you so much!