trouble with progress bars

[Vaibhav Vaish <csu96173 cse iitd ernet in>]

I'm having trouble in accessing the percentage field of progress bars. I'm
defining the following function for updating a progress bar (using
timeout)

gint move_hbar(gpointer data)
{
   gfloat hval;
   hval = GTK_PROGRESS_BAR (data)->percentage
	^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...........
}

On compiling, I get an error in the indicated line:
structure has no member `percentage'

Please let me know how to correct this. I'm using gtk+ 1.1.2.

  Vaibhav Vaish.
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