C/C++ Programmer's Guide (G06.27+, H06.03+)
Table Of Contents
- What’s New in This Manual
- About This Guide
- 1 Introduction to HP C and C++ for NonStop Systems
- TNS C Language System
- TNS C++ Language System
- TNS/R Native C and C++ Language System
- TNS/R Native C Compiler
- TNS/R Native C++ Compiler
- TNS/R Native C Run-Time Library
- C++ Run-Time Library and Standard C++ Library
- TNS/R Native Linkers (nld and ld Utilities)
- Inspect Symbolic Debugger
- Visual Inspect Symbolic Debugger
- TNS/R Native Object File Tool (noft Utility)
- NonStop SQL/MP Compiler and NonStop SQL/MX Compiler
- TNS/R Native C and C++ Migration Tool
- Features of TNS/R Native C and C++
- TNS/E Native C and C++ Language System
- TNS/E Native C Compiler
- TNS/E Native C++ Compiler
- TNS/E Native C Run-Time Library
- C++ Run-Time Library and Standard C++ Library
- TNS/E Native Linker (eld Utility)
- Native Inspect Symbolic Debugger
- Visual Inspect Symbolic Debugger
- TNS/E Native Object File Tool (enoft Utility)
- NonStop SQL/MP Compiler and NonStop SQL/MX Compiler
- TNS/E Native C and C++ Migration Tool
- Features of TNS/E Native C and C++
- Writing Portable Programs
- Porting Programs to HP C and C++ for NonStop Systems
- Porting Without Data Alignment Problems
- Guardian and OSS Environment Interoperability
- 2 C and C++ Extensions
- 3 Interfacing to Guardian Procedures and OSS Functions
- 4 Using the C Run-Time Library
- 5 Using the Standard C++ Library
- 6 Accessing Middleware Using HP C and C++ for NonStop Systems
- 7 Mixed-Language Programming for TNS Programs
- 8 Mixed-Language Programming for TNS/R and TNS/E Native Programs
- 9 System-Level Programming
- 10 Converting C-Series TNS Programs to Use the Current TNS Compiler
- 11 Migrating Programs to TNS/R or TNS/E Native Mode
- 12 Preprocessor Directives and Macros
- 13 Compiler Pragmas
- ALLOW_CPLUSPLUS_COMMENTS
- ALLOW_EXTERN_EXPLICIT_INSTANTIATION
- ANSICOMPLY
- ANSISTREAMS
- BUILD_NEUTRAL_LIBRARY
- CALL_SHARED
- CHECK
- COLUMNS
- CPATHEQ
- CPPONLY
- CSADDR
- ELD(arg)
- ENV
- ERRORFILE
- ERRORS
- EXTENSIONS
- EXTERN_DATA
- FIELDALIGN
- FORCE_VTBL
- FORCE_STATIC_TYPEINFO
- FORCE_STATIC_VTBL
- FUNCTION
- HEADERS
- HEAP
- HIGHPIN
- HIGHREQUESTERS
- ICODE
- IEEE_FLOAT
- INLINE
- INLINE_COMPILER_GENERATED_FUNCTIONS
- INLINE_LIMIT
- INLINE_STRING_LITERALS
- INNERLIST
- INSPECT
- KR
- LARGESYM
- LD(arg)
- LINES
- LINKFILE
- LIST
- LMAP
- MAP
- MAPINCLUDE
- MAXALIGN
- MIGRATION_CHECK
- NEST
- NEUTRAL
- NLD(arg)
- NOEXCEPTIONS
- NON_SHARED
- OLDCALLS
- OLIMIT
- ONCE
- OPTFILE
- OPTIMIZE
- OVERFLOW_TRAPS
- PAGE
- POOL_STRING_LITERALS
- POP
- PUSH
- REFALIGNED
- REMARKS
- RUNNABLE
- RUNNAMED
- RVU
- SAVEABEND
- SEARCH
- SECTION
- SHARED
- SQL
- SQLMEM
- SRL
- SRLExportClassMembers
- SRLExports
- SRLName
- SSV
- STDFILES
- STRICT
- SUPPRESS
- SUPPRESS_VTBL
- SYMBOLS
- SYNTAX
- SYSTYPE
- TANDEM_FLOAT
- TRIGRAPH
- VERSION1
- VERSION2
- VERSION3
- WARN
- WIDE
- XMEM
- XVAR
- 14 Compiling, Binding, and Accelerating TNS C Programs
- 15 Compiling, Binding, and Accelerating TNS C++ Programs
- 16 Compiling and Linking TNS/R Native C and C++ Programs
- 17 Compiling and Linking TNS/E Native C and C++ Programs
- 18 Using ETK and Native C/C++ Cross Compiler on the PC
- 19 Running and Debugging C and C++ Programs
- 20 TNS C Compiler Messages
- 21 Native C and C++ Compiler Messages
- 22 Run-Time Messages
- 23 Handling TNS Data Alignment
- A HP C Implementation-Defined Behavior
- Implementation-Defined Behavior of Native C
- G.3.1 Translation
- G.3.2 Environment
- G.3.3 Identifiers
- G.3.4 Characters
- G.3.5 Integers
- G.3.6 Floating Point
- G.3.7 Arrays and Pointers
- G.3.8 Registers
- G.3.9 Structures, Unions, Enumerations, and Bit Fields
- G.3.10 Qualifiers
- G.3.11 Declarators
- G.3.12 Statements
- G.3.13 Preprocessing Directives
- G.3.14 Library Functions
- G.4 Locale Behavior
- G.5 Common Extensions
- Translation Limits for Native C Compilers
- Implementation-Defined Behavior of TNS C
- G.3.1 Translation
- G.3.2 Environment
- G.3.3 Identifiers
- G.3.4 Characters
- G.3.5 Integers
- G.3.6 Floating Point
- G.3.7 Arrays and Pointers
- G.3.8 Registers
- G.3.9 Structures, Unions, Enumerations and Bit Fields
- G.3.10 Qualifiers
- G.3.11 Declarators
- G.3.12 Statements
- G.3.13 Preprocessing Directives
- G.3.14 Library Functions
- G.4 Locale Behavior
- G.5 Common Extensions
- Implementation-Defined Behavior of Native C
- B TNS C++ ImplementationDefined Behavior
- C ASCII Character Set
- D Data Type Correspondence
- E Features and Keywords of Version2NativeC++
- F MIGRATION_CHECK Messages
- Glossary
- Index
HP C/C++ Programmer’s Guide for NonStop Systems—429301-010
23-1
23 Handling TNS Data Alignment
Programs compiled with the TNS instruction set must follow the even-byte data
alignment rules of TNS compilers. Certain violations of these programming rules might
lead to run-time errors. This section describes these violations and explains how to
avoid them and how to diagnose them at run time.
On TNS systems, a word is 16 bits. The TNS instruction set includes data access
instructions that expect 32-bit byte addresses that must be even-byte aligned (that is,
aligned 0 modulo 2) for correct operation. In TNS mode and Accelerator mode,
addresses that are odd-byte aligned (that is, aligned 1 modulo 2) are called misaligned.
TNS processors consistently “round down” misaligned addresses (that is, they ignore
the low-order bit).
TNS/R and TNS/E processors handle misaligned addresses of TNS programs
inconsistently, rounding down some but not others and behaving differently in TNS
mode and accelerated mode. Compilers cannot catch misaligned addresses that are
computed at run time.
The behavior of TNS programs with misaligned addresses on TNS/R or TNS/E
processors is almost impossible to predict. If you are not sure that your program has
only aligned addresses, you can use the tracing facility to detect whether programs are
using misaligned pointers, and if so, where. You should then change the programs to
avoid misalignment.
The round-downs occur only in TNS-compiled C and C++ programs, native C or C++
programs. In native mode, misalignments can slow down a program, but they cannot
cause errors.
The data misalignment issue might affect programs that use these HP products. If you
use these products, see the appropriate manual or addendum:
Product Number Manual or Addendum
TNS C T9255 This manual
TNS C++ T9541 This manual
G-series TNS c89 T8629 This manual
TNS/E c89 T8164 This manual
TNS/E CCOMP T9577 This manual
TNS/E CPPCOMP T9225 This manual
TNS/R c89 T8164 This manual
TNS/R NMC T9577 This manual
TNS/R NMCPLUS T9225 This manual
Accelerator T9276 Accelerator Manual
TNS COBOL85
and OSS cobol
T9257 COBOL Manual for TNS and TNS/R