OSF DCE Application Development Guide--Core Components

Chapter 9. Using the DCE Threads Exception-

Returning Interface

DCE Threads provides the following two ways to obtain information about the status of a

threads routine:

• The routine returns a status value to the thread.

• The routine raises an exception.

Before you write a multithreaded program, you must choose only one of the preceding

two methods of receiving status. These two methods cannot be used together in the same

code module.

The POSIX P1003.4a (pthreads) draft standard speciﬁes that errors be reported to the

thread by setting the external variable errno to an error code and returning a function

value of -1. The threads reference pages document this status-value-returning interface

(see the OSF DCE Application Development Reference). However, an alternative to

status values is provided by DCE Threads in the exception-returning interface.

This chapter introduces and provides conventions for the modular use of the

exception-returning interface to DCE Threads.

9.1 Syntax for C

Access to exceptions from the C language is deﬁned by the macros in the

exc_handling.h ﬁle. The exc_handling.h header ﬁle is included automatically when

you include pthread_exc.h (see Section 9.2).

The following example shows the syntax for handling exceptions:

TRY

try_block

[CATCH (exception_name)

handler_block]...

[CATCH_ALL

handler_block]

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