libxrdeveloper's documentation
gboolean xr_value_to_value ( xr_value val,
xr_value **  nval 
)

Just a convenience interface to xr_value_ref.

Parameters:
val Value node. May be NULL, see below.
nval Pointer to the variable where value should be extracted. This pointer must not be NULL.
Returns:
This function returns FALSE if val is NULL, otherwise TRUE is returned.
Documentation for libxr, Sun Nov 28 2010 15:57:15.