Keyboard Interaction

AppGraphics provides limited support of keyboard interaction. The two main functions, described below, provide information on whether a key has been pressed and, if so, which key was pressed. Functions that normally return an ASCII code based on keypress will also return the following constants for non-alphanumeric keys (after first returning a zero as an indicator of a special key):

Key Constants

KEY_HOME

KEY_UP

KEY_PGUP

KEY_LEFT

KEY_CENTER

KEY_RIGHT

KEY_END

KEY_DOWN

KEY_PGDN

KEY_INSERT

KEY_DELETE

KEY_F1

KEY_F2

KEY_F3

KEY_F4

KEY_F5

KEY_F6

KEY_F7

KEY_F8

KEY_F9

KEY_F10

KEY_F11

KEY_F12

getch

C int getch ( )
Fortran function getch ( )

Description

Waits for and returns a keypress. This function normally returns an ASCII code for the key pressed. However, if a special key is pressed, the function will first return zero. The next call will return the code for the special key, as described above.

Return Value

C int
Fortran integer

The ASCII code for the key pressed, a zero, or, if the previous call was zero, a code for the special key pressed.

kbhit

C int kbhit ( )
Fortran function kbhit ( )

Description

Returns whether a key has been pressed since the last call to getch.

Return Value

C int
Fortran logical

Returns non-zero or .TRUE. if a keypress has occurred, zero or .FALSE. otherwise.