[sdl][S/O/FA/other]Alt and Meta keypress modifiers are ignored.

jsv · February 21, 2010, 09:47

Greetings.

There is a bug in the SDL port that prevents alt/meta modifiers from being recognized. As the code in question is shared by many variants, I think here is a good place for a bug report. Correct me if I'm wrong.

In the sdl_keypress function (main-sdl.c) we find this innocently looking code:

Code:

        /* Store the value of various modifier keys */
        bool mc = (bool)(keysym.mod & (KMOD_CTRL));
        bool ms = (bool)(keysym.mod & (KMOD_SHIFT));
        bool ma = (bool)(keysym.mod & (KMOD_ALT));
        bool mm = (bool)(keysym.mod & (KMOD_META));

It looks correct and it would work correctly if only there were built-in bool type in (pre-C99) C. But there is none and in many *bands bool is defined as char (Vanilla uses built-in boolean type when it's available, so it is not affected by this bug -- but only if compiled with something conforming to C99 standard). Values of KMOD_ALT and KMOD_META exceed 0x100. When cast to char they are truncated, so ma and mm are always zero.

This can be fixed either by using int instead of bool for flags:

Code:

    ...
    int mc = (keysym.mod & (KMOD_CTRL));
    ...

or by explicit comparison with KMOD_NONE:

Code:

    ...
    bool mc = (bool)((keysym.mod & (KMOD_CTRL) != KMOD_NONE);
    ...

IMHO, even better solution would be to get rid of bool type entirely, removing it both from *band code and C standards -- the language just do not need it. But that would be too much work.

Nick · February 21, 2010, 11:21

Thanks - fixed in FA and O dev versions.

Magnate · November 22, 2010, 20:32

Finally fixed in V (staging branch - will be in nightlies shortly).

camlost · November 22, 2010, 20:36

I guess I'm slow on the uptake; I guess I can fix this tonight when I get home

February 21, 2010, 09:47	#1
jsv Scout Join Date: Feb 2010 Location: Russia Posts: 27	[sdl][S/O/FA/other]Alt and Meta keypress modifiers are ignored. Greetings. There is a bug in the SDL port that prevents alt/meta modifiers from being recognized. As the code in question is shared by many variants, I think here is a good place for a bug report. Correct me if I'm wrong. In the sdl_keypress function (main-sdl.c) we find this innocently looking code: Code: /* Store the value of various modifier keys / bool mc = (bool)(keysym.mod & (KMOD_CTRL)); bool ms = (bool)(keysym.mod & (KMOD_SHIFT)); bool ma = (bool)(keysym.mod & (KMOD_ALT)); bool mm = (bool)(keysym.mod & (KMOD_META)); It looks correct and it would work correctly if only there were built-in bool* type in (pre-C99) C. But there is none and in many bands bool* is defined as char (Vanilla uses built-in boolean type when it's available, so it is not affected by this bug -- but only if compiled with something conforming to C99 standard). Values of KMOD_ALT and KMOD_META exceed 0x100. When cast to char they are truncated, so ma and mm are always zero. This can be fixed either by using int instead of bool for flags: Code: ... int mc = (keysym.mod & (KMOD_CTRL)); ... or by explicit comparison with KMOD_NONE: Code: ... bool mc = (bool)((keysym.mod & (KMOD_CTRL) != KMOD_NONE); ... IMHO, even better solution would be to get rid of bool* type entirely, removing it both from band code and C standards -- the language just do not need it. But that would be too much work.

February 21, 2010, 11:21	#2
Nick Vanilla maintainer Join Date: Apr 2007 Location: Canberra, Australia Age: 58 Posts: 9,529 Donated: $60	Thanks - fixed in FA and O dev versions. __________________ One for the Dark Lord on his dark throne In the Land of Mordor where the Shadows lie.

November 22, 2010, 20:36	#4
camlost Sangband 1.x Maintainer Join Date: Apr 2007 Posts: 523	I guess I'm slow on the uptake; I guess I can fix this tonight when I get home __________________ a chunk of Bronze {These look tastier than they are. !E} 3 blank Parchments (Vellum) {No french novels please.}

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November 22, 2010, 20:32	#3
Magnate Angband Devteam member Join Date: May 2007 Location: London, UK Posts: 5,079	Finally fixed in V (staging branch - will be in nightlies shortly).

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