fltk/examples/howto-add_fd-and-popen.cxx

77 lines
2.5 KiB
C++

//
// "$Id$"
//
// How to use popen() and Fl::add_fd() - erco 10/04/04
// Originally from erco's cheat sheet, permission by author.
//
// Shows how the interface can remain "alive" while external
// command is running and outputing occassional data. For instance,
// while the command is running, keyboard navigation works,
// text can be highlighted, and the interface can be resized.
//
// Copyright 2010 Greg Ercolano.
// Copyright 1998-2010 by Bill Spitzak and others.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file. If this
// file is missing or damaged, see the license at:
//
// http://www.fltk.org/COPYING.php
//
// Please report all bugs and problems on the following page:
//
// http://www.fltk.org/str.php
//
#include <stdio.h>
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Multi_Browser.H>
#ifdef WIN32
# define PING_CMD "ping -n 10 localhost" // 'slow command' under windows
# ifdef _MSC_VER
# define popen _popen
# define pclose _pclose
# else /*_MSC_VER*/
# include <unistd.h> // non-MS win32 compilers (untested)
# endif /*_MSC_VER*/
#else
# include <unistd.h>
# define PING_CMD "ping -i 2 -c 10 localhost" // 'slow command' under unix
#endif
// GLOBALS
FILE *G_fp = NULL;
// Handler for add_fd() -- called whenever the ping command outputs a new line of data
// Note: FL_SOCKET as 1st argument is used to fix a compiler error(!) on Windows 64-bit.
// Unfortunately we need this in FLTK 1.3 - should hopefully be fixed in 1.4 with a better solution.
void HandleFD(FL_SOCKET fd, void *data) {
Fl_Multi_Browser *brow = (Fl_Multi_Browser*)data;
char s[1024];
if ( fgets(s, 1023, G_fp) == NULL ) { // read the line of data
Fl::remove_fd(fileno(G_fp)); // command ended? disconnect callback
pclose(G_fp); // close the descriptor
brow->add(""); brow->add("<<DONE>>"); // append msg indicating command finished
return;
}
brow->add(s); // line of data read? append to widget
}
int main(int argc, char *argv[]) {
Fl_Window win(600,600);
Fl_Multi_Browser brow(10,10,580,580);
if ( ( G_fp = popen(PING_CMD, "r") ) == NULL ) { // start the external unix command
perror("popen failed");
return(1);
}
Fl::add_fd(fileno(G_fp), HandleFD, (void*)&brow); // setup a callback for the popen()ed descriptor
win.resizable(brow);
win.show(argc, argv);
return(Fl::run());
}
//
// End of "$Id$".
//