| **Navigation:**  [[introduction.htm|Language Reference]] > 13 - Built-in Functions >====== ALERT (set event generation key) ====== | [[age  return age from base date .htm|{{btn_prev_n.gif|Previous page}}]][[introduction.htm|{{btn_home_n.gif|Return to chapter overview}}]][[alias  set alternate keycode .htm|{{btn_next_n.gif|Next page}}]] |
|  ||

{{newc7.jpg|NewC7.jpg}}

**ALERT(**[//first-keycode//] [,//last-keycode//]**)**

{{blk2blue.jpg|blk2blue.jpg}}

| **ALERT** | Specifies keys that generate an event. |
| //first-keycode// | A numeric keycode or keycode equate label. This may be the lower limit in a range of keycodes. |
| //last-keycode// | The upper limit keycode, or keycode equate label, in a range of keycodes. |

**ALERT** specifies a key, or an inclusive range of keys, as event generation keys for the currently active window. The ALERT statement with no parameters clears all ALERT keys. The current list of key codes can be found in the [[keycode equates list.htm|KEYCODES.CLW]] source file.

Two field-independent events, EVENT:PreAlertKey and EVENT:AlertKey, generate when the user presses the ALERTed key (in that order). If the code does not execute a CYCLE statement when processing EVENT:PreAlertKey, you "shortstop" the library's default action on the alerted keypress. If the code does execute CYCLE when processing EVENT:PreAlertKey, the library performs its default action for the alerted keypress. In either case, EVENT:AlertKey generates following EVENT:PreAlertKey.

Any key with a keycode may be used as the parameter of an ALERT statement. ALERT generates field-independent events, since it is not associated with any particular control. When EVENT:AlertKey is generated by an ALERT key, the USE variable of the control that currently has input focus is not automatically updated (use UPDATE if this is required).

The ALERT statement alerts its keys separately from the ALRT attribute of a window or control. This means that clearing all ALERT keys has no effect on any keys alerted by ALRT attributes.

**Example:**

**Screen WINDOW,ALRT(F10Key),ALRT(F9Key) !F10 and F9 alerted**

**        LIST,AT(109,48,50,50),USE(?List),FROM(Que),IMM**

**        BUTTON('&Ok'),AT(111,108,,),USE(?Ok)**

**        BUTTON('&Cancel'),AT(111,130,,),USE(?Cancel)**

**       END**

** CODE**

** OPEN(Screen)**

** ****ALERT****                    !Turn off all alerted keys**

** ****ALERT****(F1Key,F12Key)      !Alert all function keys**

** ****ALERT****(279)               !Alert the Ctrl-Esc key**

** ACCEPT**

**  CASE EVENT()**

**  OF EVENT:PreAlertKey    !Pre-check alert events**

**   IF KEYCODE() <;> F4Key  !Dis-Allow F4 key standard library action, and allow **

**    CYCLE                 !all other F keys to perform their standard functions**

**   END**

**  OF EVENT:AlertKey       !Alert processing**

**   CASE KEYCODE()**

**   OF 279                 !Check for Ctrl+Esc**

**    BREAK**

**   OF F9Key               !Check for F9**

**    F9HotKeyProc          !Call hot key procedure**

**   OF F10Key              !Check for F10**

**    F10HotKeyProc         !Call hot key procedure**

**   END**

**  END**

** END**

**See Also:**

[[update  write from screen to use variables .htm|UPDATE]]

[[alrt  set window  hot  keys .htm|ALRT]]