Functions and Directives Functions and Directives

Function SetCancel() Foundation

Sets or returns whether the program can be terminated using Alt+C or Ctrl+Break.

Syntax
SetCancel( [<lToggle>] ) --> lOldSetCancel
Parameters
<lToggle>
The logical expression <lToggle> determines whether a program can be terminated at runtime by the key combination Alt+C. When the value of <lToggle> is .T. (true), this key combination terminates the application, otherwise it does not. By default an Xbase++ application can be terminated with Alt+C.
Return

When SetCancel() is called without an argument, the function returns the current setting as a logical value. If <lToggle> is specified, the new setting specified by <lToggle> is set, and the value of the old setting is returned.

Description

The environment function SetCancel() sets or removes the key combination Alt+C as a method to terminate a program. In the production version of applications, the Alt+C key combination should generally be disabled as a method to terminate the application, in order to force the user to leave the application by normal means.

Examples
SetCancel() 
// The example shows a typical use of SetCancel(). When the 
// #define constant DEBUG is set, the program can be terminated 
// with Alt+C. When the constant is not defined (as is done for 
// the final production version), the program can no longer be 
// terminated with Alt+C. 

#include "Inkey.ch" 

PROCEDURE Main 
   LOCAL nKey := 0 

   #ifndef DEBUG                     // no debug version 
      SetCancel(.F.)                 // turn off Alt+C 
   #endif 

   DO WHILE nKey <> K_ESC 
      nKey := Inkey(0) 
      ? "The inkey code of the last key is:", nKey 
   ENDDO 

RETURN
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