About dynamic memory management in FLTK

[barisurum]

Hello people;

I recently started learning gui programming in FLTK. I have a question about DMM in this example (main program):


// FLTK text program. (text output field).
// 0.1.4

#include <Fl/Fl.H>
#include <Fl/Fl_Window.H>
#include "textoutput.h"
#include "box.h"



int main( int argc, char ** argv )
{
//OBJ
Fl_Window * textWindow_OBJ_PTR = new Fl_Window( 800, 600 );
Box * textBox_OBJ_PTR = new Box( 10, 10, 300, 50, "FLTK TEXT" );
TextOutput * textOutput_OBJ_PTR = new TextOutput( 10, 80, 350, 30, "An example text output! You can't edit this :)" );

textWindow_OBJ_PTR ->end();
textWindow_OBJ_PTR ->show();


return Fl::run();

delete textBox_OBJ_PTR; textBox_OBJ_PTR = 0;
delete textOutput_OBJ_PTR; textOutput_OBJ_PTR = 0;
delete textWindow_OBJ_PTR; textWindow_OBJ_PTR = 0;
}

First I dynamically allocate a window directly from the main program as you can see.

Then I dynamically allocate a title box and a text field object which are defined and implemented in their respective header and cpp files (textoutput.h, textoutput.cpp, box.h, box.cpp). In those files I again dynamically allocate respective Fl_Box and Fl_Output objects.

And then I delete all the objects from memory in main program.

Question 1: Is this approach a sane and correct one?

Question 2: Does FLTK automatically deallocate the memory of the window (and objects tied to this hierarchy) when return FL::run() returns?

[dwhitney67]

This is the last statement that will be executed in the main() function:


return Fl::run();

Any code appearing after this statement will not be executed.

Perhaps it would be better to write the code as:


int main(int argc, char** argv)
{
...

int rtn= Fl::run();

delete textBox_OBJ_PTR; textBox_OBJ_PTR = 0;
delete textOutput_OBJ_PTR; textOutput_OBJ_PTR = 0;
delete textWindow_OBJ_PTR; textWindow_OBJ_PTR = 0;

return rtn;
}


IMO, the 'delete' statements are not really necessary since the program is exiting; this memory will be collected by the system for use by other applications. It's only when the application is in continuous operation that you need to worry about memory leaks.

[barisurum]

Thanks dwhitney.