typedef struct{
Uint8 scancode;
SDLKey sym;
SDLMod mod;
Uint16 unicode;
} SDL_keysym;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.\n");
}
UNICODE translation does have a slight overhead so don't enable it unless its needed.