#include <string.h>
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Multi_Browser.H>
#include <FL/Fl_Light_Button.H>
#include <FL/fl_ask.h>

// Demonstrate running a command from a button - erco 03/03/09
// (Response on fltk.general..)

Fl_Window        *G_win = 0;
Fl_Multi_Browser *G_out = 0;
Fl_Light_Button  *G_but = 0;
FILE             *G_fp  = 0;
const char       *G_cmd = "ping -c 10 -i 3 localhost";	// or "make -j4 .."

void HandleFD(int fd, void *) {
    char results[1024];
    if ( fgets(results, 1023, G_fp) == NULL ) {
	Fl::remove_fd(fileno(G_fp));		// remove fd
        pclose(G_fp); G_fp = 0;			// close up
        G_win->cursor(FL_CURSOR_DEFAULT);	// normal cursor
	G_but->value(0);			// button light off
        G_but->activate();			// reactivate
        return;					// back to FLTK
    }
    char *crlf = strchr(results, '\n');
    if ( crlf ) *crlf = 0;
    G_out->add(results);
}

void Run_CB(Fl_Widget*,void*) {
    if ( ( G_fp = popen(G_cmd, "r") ) == NULL ) {
        fl_message("popen failed");
	return;
    }
    // COMMAND RUNNING: DEACTIVATE BUTTON, WAIT CURSOR, ADD_FD
    G_but->deactivate();			// gray out button
    G_win->cursor(FL_CURSOR_WAIT);		// timer cursor
    G_out->clear();				// clear output
    Fl::add_fd(fileno(G_fp), HandleFD, 0);	// tell fltk to watch popen() for data
    // NOTE: let FLTK handle everything from here
}

int main() {
    G_win = new Fl_Window(720,450);
    G_out = new Fl_Multi_Browser(10,10,700,400);
    G_but = new Fl_Light_Button(600,420,100,20,"Run");
    G_but->tooltip("Runs 10 iterations of ping,\n"
                   "then stops automatically.\n");
    G_but->callback(Run_CB);
    G_win->end();
    G_win->show();
    return(Fl::run());
}