What Is a Data Type?

A data type is a construct that is defined within the desktop database. For example, here is the definition of the XWD data type. The definition is in the configuration file /usr/dt/appconfig/types/language/xclients.dt:

DATA_ATTRIBUTES XWD
 {
 	ACTIONS				Open,Print
 	ICON					Dtxwd
 	NAME_TEMPLATE		%s.xwd
 	MIME_TYPE      	application/octet-stream
 	SUNV3_TYPE    		xwd-file
 	DESCRIPTION  		This file contains a graphics image in the XWD \
 							format. These files are typically created by \
 							taking snapshots of windows using the XwdCapture \
 							action. Its data type is named XWD. XWD files \
 							have names ending with `.xwd' or `.wd'.
 }

DATA_CRITERIA XWD1
 {
 	DATA_ATTRIBUTES_NAME			XWD
 	MODE									f
 	NAME_PATTERN						*.xwd
 }

 DATA_CRITERIA XWD2
 {
 	DATA_ATTRIBUTES_NAME			XWD
 	MODE									f
 	NAME_PATTERN						*.wd
 }

Every data type definition has two parts:

DATA_ATTRIBUTES--describes the appearance and behavior of the data type.

DATA_CRITERIA--specifies the rules (naming or content) for categorizing a file as belonging to that data type.

The DATA_ATTRIBUTES_NAME field connects the criteria to the attributes.

There can be multiple DATA_CRITERIA for a DATA_ATTRIBUTE. For example, the XWD data type has two criteria to specify two different naming criteria (NAME_PATTERN)--names ending with .xwd or .wd.