:)) Thank you for your reply. > I'm no expert, but I had the impression they used that > for inter-thread comms rather than inter-process. > I may well be wrong.
IMHO: No. > What are your language skills etc.? Learnt little c programming, 'tried to learn unix programming independently and just started to learn c++ programming. My sole purpose of learning c++ is to learn gui programming which I want to do on *nix platform. I hope the following code explains my point. http://seriss.com/people/erco/fltk/unix-bidir-dumb-terminal.cxx Thank you. :)) > On 18 Mar 2012, at 08:49, vectrum wrote: > > > Thank you. > >=20 > >> It's unlikely that both sides of the fork() call can access the > >> fltk =3D > context: > >=20 > > If I'm not mistaken, this might be the reason why my code gives > > two different output. In CLI, it prints both write calls (child > > and parent) but in eclipse, it prints only child call. > > > Quite likely - though I'd assume that your Eclipse is using gdb for the = > debugger, so you can configure that to attach to the other process too, = > or instead, if that would help you. > > > >=20 > >> What are you hoping to achieve here? > >=20 > > Well, as I've said, I try to understand how a gui library handles = > system call so in order to clarify the matter I used this simple sys = > call as an example. > > > Ah, no. fork() is about as far from a "simple" call to cope with as it = > is possible to imagine. They way it interacts with processes and stuff = > is very tricky, and means that you need to deal with IPC to get it to = > work here. > All good stuff to learn, but not the best place to start... > > > > >=20 > >> ...so you would need to use some form of IPC to allow > >> the child to write back to the GUI that =3D exists in > >> the parent process. ---(i) > >=20 > >> ...so you can use that to set up a pipe between the > >> two processes to > send =3D messages back and forth.--(ii) > >=20 > > Do I have to use the *nix native IPC call or does fltk has its > > own IPC function which I can use as a substitute if I want to > > achieve what you suggested, the two instances(i) and (ii). > > fltk does not provide wrappers for IPC ("fast" and "light" is not = > compatible with providing an abstraction of every possible OS = > function... If you need that then QT may be a better bet.) > I usually just use BSD sockets to a local port (this will work on all = > platforms we care about) or with named pipes. (The WinXX implementation = > of named pipes is "odd" but with a few #ifdef's you can make it work = > like the *nix pipes do, so again that is fairly portable...) > All the host OS's also provide some form of message queue mechanism for = > IPC too, which may suit your needs... > > > > I've heard that QT has its own signal, slot etc to handle this > > kind of job. > > I'm no expert, but I had the impression they used that for inter-thread = > comms rather than inter-process. I may well be wrong. > > > > QT also has DBus module by which it interacts with > > OS but I have no such knowledge to comprehend this, only getting > > abstruct concept while going the documents available in the web. > > Yup, DBus could do it, though it is not portable (since it really only = > exists in linux.) Pipes or sockets are simpler and more portable. > > > > The main point I try to understand is how a gui library interacts > > with unix system call and other system tools. If I develop a console > > (CLI) based program, and later implement the same program in gui then > > what I need to do. > > If you have a working CLI tool, and you have control over its inputs and = > outputs, it is often quite easy to write a GUI wrapper that runs the = > existing CLI tool, rewriting the base tool may not be necessary. > > > > Rewrite it with C++ and fltk or > > Probably not - and note that C++ can use C code "as is". Getting C to = > call C++ is trickier... If you have working C code, then invoking that = > from a C++ code is straightforward. > > > develop a gui (with > > buttons, labels, text boxes etc) and attach the native c program to > > it. > > Yes, that'd work. > > >=20 > > Bottom Line? :)) > > Do I need to know C programming in order to learn unix system = > programming using fltk and C++? > > Doing anything low-level in a unix system without a working knowledge of = > C is tricky. If you know C++, you mostly know C anyway. > What are your language skills etc.? > > > > _______________________________________________ fltk mailing list [email protected] http://lists.easysw.com/mailman/listinfo/fltk
