error

Arguments

Returns

This function does not return.

Description

The error function causes the interpreter to immediately stop what it is doing and to jump to the innermost trap_error, unwind_protect, interactive session or interprocess communication event handler. The value of _last_error_ is set to the argument string.

Example

This function will return its argument if the argument is a number, or generate an error and never return if the argument is not a number.

    function check_number (n)
    {
        if (!number_p(n))
    	{
               error(string(n," is not a number."));
    	}
        n;
    }

This statement will immediately cause an error if the user presses Ctrl-C at the keyboard. This is useful for breaking a running program and going to a debugging prompt.

    signal (SIGINT, #(error ("Keyboard Interrupt")))
    		

See Also

trap_error, unwind_protect