view docs/man3/SDL_keysym.3 @ 717:42ed44b2c8b6

Date: Sun, 14 Sep 2003 17:04:55 -0400 From: Philip D.S. Thoren <pthoren@cs.uml.edu> Reply-To: "sdl@libsdl.org" <sdl@libsdl.org> To: "sdl@libsdl.org" <sdl@libsdl.org> Subject: [SDL] BUG in src/video/windx5/SDL_dx5events.c I tracked down a bug that crashed my program on Windows *all* the time. FILE: src/video/windx5/SDL_dx5events.c FUNCTION: handle_mouse BUG: SDL_PublicSurface is being dereferenced when it is NULL. I added the following to the very begining of handle_mouse and it solved my crashing problems: if (SDL_PublicSurface == NULL) return; ~ Philip D.S. Thoren
author Ryan C. Gordon <icculus@icculus.org>
date Mon, 15 Sep 2003 13:51:25 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
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.TH "SDL_keysym" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_keysym\- Keysym structure
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint8 scancode;
  SDLKey sym;
  SDLMod mod;
  Uint16 unicode;
} SDL_keysym;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBscancode\fR
Hardware specific scancode
.TP 20
\fBsym\fR
SDL virtual keysym
.TP 20
\fBmod\fR
Current key modifiers
.TP 20
\fBunicode\fR
Translated character
.SH "DESCRIPTION"
.PP
The \fBSDL_keysym\fR structure is used by reporting key presses and releases since it is a part of the \fI\fBSDL_KeyboardEvent\fR\fR\&.
.PP
The \fBscancode\fR field should generally be left alone, it is the hardware dependent scancode returned by the keyboard\&. The \fBsym\fR field is extremely useful\&. It is the SDL-defined value of the key (see \fISDL Key Syms\fR\&. This field is very useful when you are checking for certain key presses, like so: 
.PP
.nf
\f(CW\&.
\&.
while(SDL_PollEvent(&event)){
  switch(event\&.type){
    case SDL_KEYDOWN:
      if(event\&.key\&.keysym\&.sym==SDLK_LEFT)
        move_left();
      break;
    \&.
    \&.
    \&.
  }
}
\&.
\&.\fR
.fi
.PP
 \fBmod\fR stores the current state of the keyboard modifiers as explained in \fI\fBSDL_GetModState\fP\fR\&. The \fBunicode\fR is only used when UNICODE translation is enabled with \fI\fBSDL_EnableUNICODE\fP\fR\&. If \fBunicode\fR is non-zero then this a the UNICODE character corresponding to the keypress\&. If the high 9 bits of the character are 0, then this maps to the equivalent ASCII character: 
.PP
.nf
\f(CWchar ch;
if ( (keysym\&.unicode & 0xFF80) == 0 ) {
  ch = keysym\&.unicode & 0x7F;
}
else {
  printf("An International Character\&.
");
}\fR
.fi
.PP
 UNICODE translation does have a slight overhead so don\&'t enable it unless its needed\&.
.SH "SEE ALSO"
.PP
\fI\fBSDLKey\fR\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00