[Plib-users] (cory vs. pui) The attack of setValuator

[cory b. <co...@gm...>]

I found the following in the PUI documentation today:
There are many occasions when you'd really like to have the PUI widget
directly drive and/or reflect the value of some memory location in the
application code. These calls let you do that:

  void puObject::setValuator ( int   *i ) ;
  void puObject::setValuator ( float *f ) ;
  void puObject::setValuator ( char  *s ) ;


Once you make one of these calls, PUI will automatically update the
memory location indicated with the current value of the widget
whenever it changes - and also update the appearance of the widget to
reflect the value stored in that memory location whenever the widget
is redrawn. This is often a lot more convenient than using a callback
function to register changes in the widget's value.

So I tried it out:
//global variable
float update = 1.0f;

//initialize my puInput inside a function
	//hertz text input
	hertz_text = new puInput ( curx, cury,
							curx + PUI_TEXT_WIDTH,
							cury + PUI_TEXT_HEIGHT ) ;
	hertz_text->setValuator( &update );
	hertz_text->setLabel( "Hertz" );
	hertz_text->setLabelPlace( PUPLACE_TOP_CENTERED );


This compiles, and runs.

It seems to work correctly as long as I do not remove all of the
characters from the puInput box. However if I am trying to change the
value, when I am typing in the new value, if the new value ever
becomes a non valid float value, then the program crashes. For example
if I want to change 1.0 to 2.0 and I delete 1.0 so I can type 2.0,
then instant crash. I can change from 1.0 to 2.0 if I type the 2 after
the 1, and then erase the 1.

Searching the mail archives and googling didn't help, so I am posting here.

I suspect either my weak understanding of pointers means that I am
passing an incorrect argument to the setValuator function, or maybe
the puInput object is writing invalid data to the update variable.

Please let me know how to fix this.

thanks,

Cory