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NULL Data Objects

The NULL Data Object differs from all of the others for several reasons:

  1. It is not defined in the Object Editor
  2. It has no Arguments
  3. It has no Results Data

Uses for the NULL Data Object

The primary use for a NULL Data Object is to play a Template without binding to one of the other Data Objects. This enables the CGI to maintain state. For example, if data is being passed from HTML document to HTML document in hidden elements, this will enable the chain to remain intact. If the URL of the HTML document was called instead of calling the CGI, the chain would be broken.

Another use of the NULL Data Object is when the developer wants to populate a Template's Data Sites with data not produced from any Data Object Type. This is accomplished by registering Data Sites with one of the following functions, and supplying their value:

int SaRegisterStringSite(char* file, 
								char* site, 
						char* value);

int SaRegisterFuncSite(char* file, 
						char* site, 
						SaSiteCallback func, 
						void* client);
See the last chapter of this Manual for specific API explanations.


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