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.