
Class documentation.

$Ident: This file is part of the 'Gt-library' 1.0.0 $
$Copyright: (C) 1997 by Gran Gustafsson $

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  ** GtBase **
  ------------

Name:       GtBase
Superclass: <none>
Include:    gtbase.h


  This class is an abstract base class for many of the classes in the
Gt-library. It presents a somewhat standard method interface with tags to
the user. Some introspective methods are also provided by this class.


Tags for GtBase:
----------------
  
  ** NONE DEFINED **
  
  
Callbacks for GtBase:
---------------------
  
  ** NONE DEFINED **
  
  
Methods for GtBase:
-------------------

   -- User methods --
  
  sbool Init(GtTag *tgs)
  sbool Set(GtTag *tgs)
  void Get(GtTag *tgs)
  char *GetClass(void)
  sbool IsSubClassOf(char *cn)
  sbool InitV(ulong tag,...)
  sbool SetV(ulong tag,...)
  void GetV(ulong tag,...)
  long GetA(ulong tag,long def)

   -- Internal methods --
   
  void PrtErrHeader(void)

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  sbool Init(GtTag *tgs)
  
    - tgs : pointer to a tag list.
    
    - <result> : true if the initialization was successful else false.
    
    This method will initialize a new instance according to the tag list.

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  sbool Set(GtTag *tgs)

    - tgs : pointer to a tag list.
    
    - <result> : true if setting the attributes were successful else false.
                   
    This method will set attributes of the instance according to the tag
    list.
    
 ----------------------------------------------------------------------------

  void Get(GtTag *tgs)

    - tgs : pointer to a tag list.
    
    This method will get the values of instance attributes according to the
    tag list. Each value in the tag list is a pointer to where to put the
    attribute's value. The position to put an attributes value is usually a
    32-bit long (only a very limited number of attributes gives a value
    other than a 32-bit long when gotten).
    
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  char *GetClass(void)

    - <result> : pointer to a constant string.
     
    This method returns a string with the class' name.
    
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  sbool IsSubClassOf(char *cn)

    - cn : pointer to a string with a class name.
    
    - <result> : true if the instance is of or is a subclass of the named
                 class else false.
    
    This method return true if the asked instance is of the named class or
    if it is a subclass of the named class.
    
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  sbool InitV(ulong tag,...)

    - tag : first tag identifier followed by it's value and then the second
            tag identifier followed by it's value and so on.
            
    - <result> : as from "Init()" above.
    
    This method creates a normal tag list and then calls the "Init()" method
    as described above.

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  sbool SetV(ulong tag,...)

    - tag : first tag identifier followed by it's value and then the second
            tag identifier followed by it's value and so on.
            
    - <result> : as from "Set()" above.
    
    This method creates a normal tag list and then calls the "Set()" method
    as described above.

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  void GetV(ulong tag,...)

    - tag : first tag identifier followed by it's value and then the second
            tag identifier followed by it's value and so on.
            
    - <result> : as from "Get()" above.
    
    This method creates a normal tag list and then calls the "Get()" method
    as described above.

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  long GetA(ulong tag,long def)
  
    - tag : tag identifier for the attribute to get.
    - def : default value if the attribute could not be found.
    
    - <result> : the value of the requested attribute or the default value.
                   
    This method uses the normal "Get()" method to get an attribute value into
    a internal variable. This value is then returned to the caller.
    
    Note that the internal variable is only a 32-bit long and attributes
    that return larger values can not be handled by this method.
    
 ----------------------------------------------------------------------------

  void PrtErrHeader(void)
  
    This method prints a leading header line for a error message from the
    Gt-library. It is called by the "GtError()" function if it is given a
    object pointer as first argument.
