key - Array of flags indicating key state. Allegro game programming library.

       Array  of  flags  indicating  the state of each key, ordered by scancode.  Wherever possible these values
       will be updated asynchronously, but  if  keyboard_needs_poll()  returns  TRUE,  you  must  manually  call
       poll_keyboard()   to   update   them  with  the  current  input  state.  The  scancodes  are  defined  in
       allegro/keyboard.h as a series of KEY_* constants (and are also listed below).  For  example,  you  could
       write:

          if (key[KEY_SPACE])
             printf("Space is pressed\n");

       Note  that the array is supposed to represent which keys are physically held down and which keys are not,
       so it is semantically read-only.

       These are the keyboard scancodes:

          KEY_A ... KEY_Z,
          KEY_0 ... KEY_9,
          KEY_0_PAD ... KEY_9_PAD,
          KEY_F1 ... KEY_F12,

          KEY_ESC, KEY_TILDE, KEY_MINUS, KEY_EQUALS,
          KEY_BACKSPACE, KEY_TAB, KEY_OPENBRACE, KEY_CLOSEBRACE,
          KEY_ENTER, KEY_COLON, KEY_QUOTE, KEY_BACKSLASH,
          KEY_BACKSLASH2, KEY_COMMA, KEY_STOP, KEY_SLASH,
          KEY_SPACE,

          KEY_INSERT, KEY_DEL, KEY_HOME, KEY_END, KEY_PGUP,
          KEY_PGDN, KEY_LEFT, KEY_RIGHT, KEY_UP, KEY_DOWN,

          KEY_SLASH_PAD, KEY_ASTERISK, KEY_MINUS_PAD,
          KEY_PLUS_PAD, KEY_DEL_PAD, KEY_ENTER_PAD,

          KEY_PRTSCR, KEY_PAUSE,

          KEY_ABNT_C1, KEY_YEN, KEY_KANA, KEY_CONVERT, KEY_NOCONVERT,
          KEY_AT, KEY_CIRCUMFLEX, KEY_COLON2, KEY_KANJI,

          KEY_LSHIFT, KEY_RSHIFT,
          KEY_LCONTROL, KEY_RCONTROL,
          KEY_ALT, KEY_ALTGR,
          KEY_LWIN, KEY_RWIN, KEY_MENU,
          KEY_SCRLOCK, KEY_NUMLOCK, KEY_CAPSLOCK

          KEY_EQUALS_PAD, KEY_BACKQUOTE, KEY_SEMICOLON, KEY_COMMAND

       Finally, you may notice an `odd' behaviour of the KEY_PAUSE key. This key  only  generates  an  interrupt
       when  it  is  pressed,  not  when  it  is released.  For this reason, Allegro pretends the pause key is a
       `state' key, which is the only way to make it usable.

       key - Array of flags indicating key state. Allegro game programming library.

install_keyboard(3alleg4), poll_keyboard(3alleg4), key_shifts(3alleg4)

Allegro                                           version 4.4.3                                     key(3alleg4)

#include<allegro.h>externvolatilecharkey[KEY_MAX];