Using an Extended Keyboard

Vermont Views supports the additional functionality provided by the extended keyboard. During initialization, vv_init(), by default, checks if an extended keyboard is present. If it is, a global flag is set. The Vermont Views functions that read the keyboard use the value of this flag to determine the proper DOS BIOS interrupt needed to read the keyboard.

The default is for vv_init() to check for the extended keyboard. To disable this check, call:

init_nochk(KB_EXTEND);

before calling vv_init() in your main program.

The differences between the standard keyboard and the extended keyboard and how Vermont Views handles these differences are as follows:

• nF11 and F12 are provided on the extended keyboard but not on the standard keyboard. The keycodes returned for these keys are KEY_F11 and KEY_F12, respectively. Keycode values for these functions keys when modified with the Shift, Alt, and Ctrl keys are provided.
  
  
• nSeveral keys are found in two places on the extended keyboard where they are only found once on the standard keyboard. These keys include the following: Enter, /, Home, End, PgUp, PgDn, Up arrow, Down arrow, Left arrow, Right arrow, Ins, and Del. Vermont Views returns exactly the same keycode for each of the pairs of keys. For instance, both PgDn keys return KEY_PGDN.
  
  
• nAdditional modifier keys are provided and recognized by the extended keyboard. For instance, there are two Alt keys, one on the left of the keyboard and one on the right. ki_stat() recognizes these differences.