Defining Version Compatibility for Your Printing Extension(IM:XP)

Inside Macintosh: QuickDraw GX Printing Extensions and Drivers /: Chapter 2 - Printing Extensions / Using Resources in Printing Extensions

Defining Version Compatibility for Your Printing Extension
Your printing extension must contain at least one version ('vers') resource that defines its compatibility with QuickDraw GX. Version resources are used to record version information for Macintosh applications. You need to include a version resource with an ID of gxPrintingExtensionBaseID that defines with which version of QuickDraw GX your extension is compatible.

IMPORTANT
You must include the version resource or your extension will not load.
For the current version, the value of the first byte of the resource definition must be either 1 or 0. Listing 2-19 shows the version resource that defines QuickDraw GX compatibility for the background picture printing extension.
Listing 2-19 The QuickDraw GX version resource for the background picture printing extension
resource 'vers' (gxPrintingExtensionBaseID, sysHeap, purgeable) {
   0x0,
   0x0,
   release,
   0x0,
   verUS,
   "",
   ""};
You can also include standard version resources in the resource files for your printing extension. These resources are described in Inside Macintosh: Macintosh Toolbox Essentials. Listing 2-20 shows the standard version resources for the background picture printing extension.
Listing 2-20 The standard version resources for the background picture printing extension
resource 'vers' (1, sysHeap, purgeable) {
   0x1,
   0x0,
   beta,
   0x2,
   verUS,
   "1.0b2",
   "1.0b2, © Apple Computer, Inc.  1992-1993"};
resource 'vers' (2, sysHeap, purgeable) {
   0x1,
   0x0,
   beta,
   0x2,
   verUS,
   "1.0b2",
   "Backwash v1.0b2"};