Document revision date: 30 March 2001

Chapter 4
4	OpenVMS Argument Data Types
4.1	Atomic Data Types
4.2	String Data Types
4.3	Miscellaneous Data Types
4.4	Reserved Data-Type Codes
4.4.1	Facility-Specific Data-Type Codes
4.5	Varying Character String Data Type (DSC$K_DTYPE_VT)
Chapter 5
5	OpenVMS Argument Descriptors
5.1	Descriptor Prototype
5.2	Fixed-Length Descriptor (CLASS_S)
5.3	Dynamic String Descriptor (CLASS_D)
5.4	Array Descriptor (CLASS_A)
5.5	Procedure Argument Descriptor (CLASS_P)
5.6	Decimal String Descriptor (CLASS_SD)
5.7	Noncontiguous Array Descriptor (CLASS_NCA)
5.8	Varying String Descriptor (CLASS_VS)
5.9	Varying String Array Descriptor (CLASS_VSA)
5.10	Unaligned Bit String Descriptor (CLASS_UBS)
5.11	Unaligned Bit Array Descriptor (CLASS_UBA)
5.12	String with Bounds Descriptor (CLASS_SB)
5.13	Unaligned Bit String with Bounds Descriptor (CLASS_UBSB)
5.14	Reserved Descriptor Class Codes
5.14.1	Facility-Specific Descriptor Class Codes
Chapter 6
6	OpenVMS Conditions
6.1	Condition Values
6.1.1	Interpretation of Severity Codes
6.1.2	Use of Condition Values
6.2	Condition Handlers
6.3	Condition Handler Options
6.4	Operations Involving Condition Handlers
6.4.1	Establishing a Condition Handler
6.4.2	Reverting to the Caller's Handling
6.4.3	Signaling a Condition
6.4.4	Signaling a Condition Using GENTRAP (Alpha Only)
6.4.5	Condition Handler Search
6.5	Properties of Condition Handlers
6.5.1	Condition Handler Parameters and Invocation
6.5.1.1	Signal Argument Vector
6.5.1.2	Mechanism Argument Vector
6.5.1.3	Mechanism Depth for Alpha and VAX Handler Arguments
6.5.2	System Default Condition Handlers
6.5.3	Coordinating the Handler and Establisher
6.5.3.1	Use of Memory
6.5.3.2	Exception Synchronization (Alpha Only)
6.5.3.3	Continuation from Exceptions (Alpha Only)
6.6	Returning from a Condition Handler
6.7	Request to Unwind from a Signal
6.7.1	Signaler's Registers
6.7.2	Unwind Completion
6.8	GOTO Unwind Operations (Alpha Only)
6.8.1	Handler Invocation During a GOTO Unwind
6.8.2	Unwind Completion
6.9	Multiple Active Signals
6.10	Multiple Active Unwind Operations
Index
Index
Examples
3-1	Code for Examining the Procedure Value
3-2	Entry Code for a Stack Frame Procedure
3-3	Entry Code for a Register Frame Procedure
3-4	Exit Code Sequence for a Stack Frame
3-5	Exit Code Sequence for a Register Frame
Figures
2-1	Stack Frame Generated by CALLG or CALLS Instruction
2-2	Argument List Format
3-1	Stack Frame Procedure Descriptor (PDSC)
3-2	Fixed-Size Stack Frame Format
3-3	Variable-Size Stack Frame Format
3-4	Register Save Area (RSA) Layout
3-5	Register Save Area (RSA) Example
3-6	Register Frame Procedure Descriptor (PDSC)
3-7	Null Frame Procedure Descriptor (PDSC) Format
3-8	Procedure Signature Information Block (PSIG)
3-9	Procedure Invocation Handle Format
3-10	Invocation Context Block Format
3-11	Argument Information Register (R25) Format
3-12	Linkage Pair Block Format
3-13	Bound Procedure Descriptor (PDSC)
4-1	Varying Character String Data Type (DSC$K_DTYPE_VT)---General Format
4-2	Varying Character String Data Type (DSC$K_DTYPE_VT) Format
5-1	Descriptor Prototype Format
5-2	Fixed-Length Descriptor Format
5-3	Dynamic String Descriptor Format
5-4	Array Descriptor Format
5-5	Procedure Argument Descriptor Format
5-6	Decimal String Descriptor Format
5-7	Noncontiguous Array Descriptor Format
5-8	Varying String Descriptor Format
5-9	Varying String Descriptor with Character String Data Type
5-10	Varying String Array Descriptor Format
5-11	Unaligned Bit String Descriptor Format
5-12	Unaligned Bit Array Descriptor Format
5-13	String with Bounds Descriptor Format
5-14	Unaligned Bit String with Bounds Descriptor Format
6-1	Format of a Condition Value
6-2	Interaction Between Handlers and Default Handlers
6-3	Signal Argument Vector --- 32-Bit Format
6-4	Signal Argument Vector --- 64-Bit Format
6-5	VAX Mechanism Vector Format
6-6	Alpha Mechanism Vector Format
Tables
2-1	VAX Register Usage
2-2	Argument-Passing Mechanisms with User Explicit Control
3-1	Alpha Integer Registers
3-2	Alpha Floating-Point Registers
3-3	Contents of Stack Frame Procedure Descriptor (PDSC)
3-4	Contents of Register Frame Procedure Descriptor (PDSC)
3-5	Contents of Null Frame Procedure Descriptor (PDSC)
3-6	Contents of the Procedure Signature Information Block (PSIG)
3-7	Function Return Signature Encodings
3-8	Native-to-Translated Conversion of the PSIG Field Values
3-9	Translated-to-Native Conversion of the PSIG Field Values
3-10	Contents of the Invocation Context Block
3-11	Contents of the Argument Information Register (R25)
3-12	Contents of the Linkage Pair Block
3-13	Contents of the Bound Procedure Descriptor (PDSC)
3-14	Argument Item Locations
3-15	Data Types and the Unused Bits in Passed Data
3-16	Data Alignment Addresses
4-1	Atomic Data Types
4-2	String Data Types
4-3	Miscellaneous Data Types
4-4	Reserved Data Types
5-1	Argument Descriptor Classes for OpenVMS Alpha and OpenVMS VAX
5-2	Contents of the Prototype Descriptor
5-3	Contents of the CLASS_S Descriptor
5-4	Contents of the CLASS_D Descriptor
5-5	Contents of the CLASS_A Descriptor
5-6	Contents of the CLASS_P Descriptor
5-7	Contents of the CLASS_SD Descriptor
5-8	Internal-to-External BINSCALE Conversion Examples
5-9	Contents of the CLASS_NCA Descriptor
5-10	Contents of the CLASS_VS Descriptor
5-11	Contents of the CLASS_VSA Descriptor
5-12	Contents of the CLASS_UBS Descriptor
5-13	Contents of the CLASS_UBA Descriptor
5-14	Contents of the CLASS_SB Descriptor
5-15	Contents of the CLASS_UBSB Descriptor
5-16	Specific OpenVMS VAX Descriptors Reserved to Compaq
6-1	Contents of the Condition Value
6-2	Value Symbols for the Condition Value Longword
6-3	Interpretation of Severity Codes
6-4	Exception Codes and Symbols for the Alpha GENTRAP Argument
6-5	Contents of the Alpha Argument Mechanism Array (MECH)

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