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Public Variable Configuration
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Declaring and Using
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Declaring and Using
Initialization of Public Variables
When a widget instance is created, all of its public variables are
initialized by the Tix Intrinsics before the
InitWidgetRec
method is
called. Therefore,
InitWidgetRec
and any other method of this widget
instance are free to assume that all the public variables have been
properly initialized and use them as such.
The public variables are initialized by the following criteria:
Step 1
If the value of the variable is specified by the
creation command, this value is used. For example, if the application
programmer has created an instance in the following way:
tixArrowButton .arr -direction n
The value
n
will be used for the -direction variable.
Step 2
if step 1 fails but the value of the variable is
specified in the options database, that value is used. For example, if
the user has created an instance in the following way:
option add *TixArrowButton.direction w
tixArrowButton .arr
The value
w
will be used for the -direction variable.
Step3
if step 2 also fails, the default value specified
in the -configspec section of the class declaration will be used.
You can use a type ckecker procedure to check whether the user has
supplied a value of the correct type for a public variable. The type
checker is specified in the -configspec section of the class
declaration after the default value.
http://tix.sourceforge.net
http://tix.sourceforge.net
