Updated: 11 December 1998

OpenVMS Programming Concepts Manual

Chapter 13
13	Distributed Name Service (VAX Only)
13.1	DECdns Clerk System Service
13.1.1	Using the DECdns System Service and Run-Time Library Routines
13.1.1.1	Using the SYS$DNS System Service
13.1.1.2	Using the Run-Time Library Routines
13.2	Using the SYS$DNS System Service Call
13.2.1	Creating Objects
13.2.2	Modifying Objects and Their Attributes
13.2.3	Requesting Information from DECdns
13.2.3.1	Using the Distributed File Service (DFS)
13.2.3.2	Reading Attributes from DNS
13.2.3.3	Enumerating DECdns Names and Attributes
13.3	Using the DCL Command DEFINE with DECdns Logical Names
Chapter 14
14	Using the Distributed Transaction Manager
14.1	Introduction to DECdtm Services
14.1.1	Sample Atomic Transaction
14.1.2	Transaction Participants
14.1.3	DECdtm System Services
14.1.4	Default Transactions
14.2	Calling DECdtm System Services
14.3	Using DECdtm Services: An Example
Chapter 15
15	Condition-Handling Routines and Services
15.1	Overview of Run-Time Errors
15.2	Overview of the OpenVMS Condition Handling Facility
15.2.1	Condition-Handling Terminology
15.2.2	Functions of the Condition Handling Facility
15.3	Exception Conditions
15.3.1	System Service Exception Conditions
15.3.1.1	Conditions Caused by Exceptions
15.3.2	Exception Conditions
15.3.3	Arithmetic Exceptions
15.3.4	Unaligned Access Traps (Alpha Only)
15.4	How Run-Time Library Routines Handle Exceptions
15.4.1	Exception Conditions Signaled from Mathematics Routines (VAX Only)
15.4.1.1	Integer Overflow and Floating-Point Overflow
15.4.1.2	Floating-Point Underflow
15.4.2	System-Defined Arithmetic Condition Handlers
15.5	Condition Values
15.5.1	Return Status Convention
15.5.1.1	Testing Returned Condition Values
15.5.1.2	Testing SS$_NOPRIV and SS$_EXQUOTA Condition Values
15.5.2	Modifying Condition Values
15.6	Exception Dispatcher
15.7	Argument List Passed to a Condition Handler
15.8	Signaling
15.8.1	Generating Signals with LIB$SIGNAL and LIB$STOP
15.8.2	Signal Argument Vector
15.8.3	VAX Mechanism Argument Vector (VAX Only)
15.8.4	Alpha Mechanism Argument Vector (Alpha Only)
15.8.5	Multiple Active Signals
15.9	Types of Condition Handlers
15.9.1	Default Condition Handlers
15.9.2	Interaction Between Default and User-Supplied Handlers
15.10	Types of Actions Performed by Condition Handlers
15.10.1	Unwinding the Call Stack
15.10.2	GOTO Unwind Operations (Alpha Only)
15.11	Displaying Messages
15.11.1	Chaining Messages
15.11.2	Logging Error Messages to a File
15.11.2.1	Creating a Running Log of Messages Using SYS$PUTMSG
15.11.2.2	Suppressing the Display of Messages in the Running Log
15.11.3	Using the Message Utility to Signal and Display User-Defined Messages
15.11.3.1	Creating the Message Source File
15.11.3.1.1	Specifying the Facility
15.11.3.1.2	Specifying the Severity
15.11.3.1.3	Specifying Condition Names and Messages
15.11.3.1.4	Specifying Variables in the Message Text
15.11.3.1.5	Compiling and Linking the Messages
15.11.3.1.6	Linking the Message Object Module
15.11.3.1.7	Accessing the Message Object Module from Multiple Programs
15.11.3.1.8	Modifying a Message Source Module
15.11.3.1.9	Accessing Modified Messages Without Relinking
15.11.4	Signaling User-Defined Values and Messages with Global and Local Symbols
15.11.4.1	Signaling with Global Symbols
15.11.4.2	Signaling with Local Symbols
15.11.4.3	Specifying FAO Parameters
15.12	Writing a Condition Handler
15.12.1	Continuing Execution
15.12.2	Resignaling
15.12.3	Unwinding the Call Stack
15.12.4	Example of Writing a Condition Handler
15.12.4.1	Signal Array
15.12.4.2	Mechanism Array
15.12.4.3	Comparing the Signaled Condition with an Expected Condition
15.12.4.4	Exiting from the Condition Handler
15.12.4.5	Returning Control to the Program
15.12.5	Example of Condition-Handling Routines
15.13	Debugging a Condition Handler
15.14	Run-Time Library Condition-Handling Routines
15.14.1	RTL Jacket Handlers (Alpha Only)
15.14.2	Converting a Floating-Point Fault to a Floating-Point Trap (VAX Only)
15.14.3	Changing a Signal to a Return Status
15.14.4	Changing a Signal to a Stop
15.14.5	Matching Condition Values
15.14.6	Correcting a Reserved Operand Condition (VAX Only)
15.14.7	Decoding the Instruction That Generated a Fault (VAX Only)
15.15	Exit Handlers
15.15.1	Establishing an Exit Handler
15.15.2	Writing an Exit Handler
15.15.3	Debugging an Exit Handler
15.15.4	Example of an Exit Handler

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