Checking the Status of Key Modifiers (PCDOS and OS/2)

In the PCDOS and OS/2 environments, you can determine whether any of the key modifiers are currently being pressed down or one of the key modifier toggles are locked into the "on" position. The key modifiers that can be tested are as follows:

    Insert/overwrite mode

    Caps Lock

    Num Lock

    Scroll Lock

    Alt key

    Ctrl key

    Left Shift key

    Right Shift key

If using an extended keyboard, more checks are allowed.

To check the status of the different key modifiers, use the keyboard input status function, ki_stat():

int ki_stat()

This function returns an integer with bits set for each key modifier that is being held down at the moment. Each key modifier is assigned a bit mask so that you can test which key modifiers are currently pressed. The #defined names for each bit mask and what they indicate are shown in Table 41.1.

Table 41.1: Keyboard Status Bit Masks (PCDOS and OS/2)