----- Original Message ----- From: "Eli Zaretskii" <[EMAIL PROTECTED]> > > From: "Lennart Borgman" <[EMAIL PROTECTED]> > > I am trying to understand the implementation around hourglass cursors. When > > I look through eval.c, fns.c, keyboard.c, lread.c and minibuf.c I see in > > many places something like: > > > > #ifdef HAVE_X_WINDOWS > > if (display_hourglass_p) > > cancel_hourglass (); > > #endif > > > > Is this really correct? > > Yes, I think so. > > > It looks like displaying an hourglass cursor should only happen if x > > windows is available. > > What other systems? If you refer to Windows, then please see > w32fns.c, where the timer-related hourglass code is ifdef'ed away > (probably because Windows doesn't emulate well Posix timers that raise > asynchronous signals). The Windows implementation of hourglass > cursor, if I understand it correctly, is synchronous, i.e. the > redisplay code and the idle loop set and reset it. > > Of other non-X ports, the MSDOS port doesn't support this feature at > all (you cannot change the Windows mouse pointer shape from a DOS > program running on Windows, and doing so on plain DOS involves > undesirable complications). > > As for MacOS X, I don't know. > > > Maybe it would be better to remove these ifdefs and require every Emacs > > implementation to compile the lines? Does not most systems actually have the > > possibility to display hourglass cursors? If they do not could the > > implementation not just supply some dummies for the required functions? > > That'd not be a good idea, I think: firing SIGALRM signals by the > timers complicates things (e.g., you get to handle the problem of > interrupted system calls), so it shouldn't be done without a good > reason.
There is clearly something I do not understand here. I do not mean the implementation details (though I do not understand them ;-). However I can not see how hourglass support can be implemented at all if those places where you hide or show the hourglass is ifdef:ed away. Both start_hourglass and cancel_hourglass are ifdef:ed away (unless HAVE_X_WINDOW is defined). Am I perhaps misunderstanding when HAVE_X_WINDOW is defined? Can you (or someone else) please explain this a bit more? I was trying to see if hourglass support could be implemented for w32. It is really needed for a first class application like Emacs! _______________________________________________ Emacs-devel mailing list Emacs-devel@gnu.org http://lists.gnu.org/mailman/listinfo/emacs-devel
