DOKK / manpages / debian 10 / libsdl1.2-dev / SDL_keysym.3.en
SDL_keysym(3) SDL API Reference SDL_keysym(3)

SDL_keysym - Keysym structure

typedef struct{

Uint8 scancode;
SDLKey sym;
SDLMod mod;
Uint16 unicode; } SDL_keysym;

Hardware specific scancode
SDL virtual keysym
Current key modifiers
Translated character

The SDL_keysym structure is used by reporting key presses and releases since it is a part of the SDL_KeyboardEvent.

The scancode field should generally be left alone, it is the hardware dependent scancode returned by the keyboard. The sym field is extremely useful. It is the SDL-defined value of the key (see SDL Key Syms. This field is very useful when you are checking for certain key presses, like so:

.
.
while(SDL_PollEvent(&event)){

switch(event.type){
case SDL_KEYDOWN:
if(event.key.keysym.sym==SDLK_LEFT)
move_left();
break;
.
.
.
} } . .


mod stores the current state of the keyboard modifiers as explained in SDL_GetModState. The unicode is only used when UNICODE translation is enabled with SDL_EnableUNICODE. If unicode 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:

char ch;
if ( (keysym.unicode & 0xFF80) == 0 ) {

ch = keysym.unicode & 0x7F; } else {
printf("An International Character. "); }


UNICODE translation does have a slight overhead so don't enable it unless its needed.

SDLKey

Tue 11 Sep 2001, 23:00 SDL