DLI Implementation and Reference Guide - Datalogics

16.2 DLI Implementation and Reference Guide
Overview
Concepts and Facilities: Guide to the DL Pager Composition System
The Adobe PDF Library and DLI will communicate errors back to your application
program by raising an exception. For this reason, it is important that you have
exception handlers placed to catch such errors as close as possible to their source, to
detect the error as soon as possible and to limit the damage an error can cause. It is
also important that an outer error catcher be in place, as having no exception handler
when an exception is raised will cause a fatal error.
NOTE: Follow the development guidelines for error handling that are included in
the Adobe Acrobat Core API Overview. See chapter 12, “Handling Errors” for more
information.
The Adobe PDF Library provides a mechanism in “C” to define exception handlers.
This mechanism consists of bracketing the code which may cause an exception to be
raised with DURING and HANDLER, followed by a block of code to be executed only if
an exception is raised, terminated by END_HANDLER.
CAUTION: Your application must not exit from within the exception handler.
Doing so will leave the exception handler frame on the stack, eventually leading to
a stack overflow and crash. Your application should exit beyond the
END_HANDLER statement, not within the HANDLER/END_HANDLER block. See
“Risks of Function Returns within Exception Handlers” on page 16.3 following
below.