Open System Services Porting Guide (G06.24+, H06.03+)
Table Of Contents
- What’s New in This Manual
- About This Manual
- 1 Introduction to Porting
- 2 The Development Environment
- 3 Useful Porting Tools
- 4 Interoperating Between User Environments
- Purpose of Interoperability
- The OSS User Environment
- OSS Commands for the Guardian User
- Guardian Commands for the UNIX User
- OSS Pathname and Guardian Filename Conversions
- Running the OSS Shell and Commands From TACL
- Running Guardian Commands From the OSS Shell
- Running OSS Processes With Guardian Attributes
- Using OSS Commands to Manage Guardian Objects
- 5 Interoperating Between Programming Environments
- 6 OSS Porting Considerations
- 7 Porting UNIX Applications to the OSS Environment
- 8 Migrating Guardian Applications to the OSS Environment
- General Migration Guidelines
- C Compiler Issues for Guardian Programs
- Using New and Extended Guardian Procedures
- Using OSS Functions in a Guardian Program
- Interoperating With OSS Programs
- Starting an OSS Program From the Guardian Environment
- C Compiler Considerations for OSS Programs
- Porting a Guardian Program to the OSS Environment
- How Arguments Are Passed to the C or C++ Program
- Differences in the Two Run-Time Environments
- Which Run-Time Routines Are Available
- Use of Common Run-Time Environment (CRE) Functions
- Replacing Guardian Procedure Calls With Equivalent OSS Functions
- Which IPC Mechanisms Can Be Used
- Interactions Between Guardian and OSS Functions
- 9 Porting From Specific UNIX Systems
- 10 Native Migration Overview
- 11 Porting or Migrating Sockets Applications
- 12 Porting Threaded Applications
- A Equivalent OSS and UNIX Commands for Guardian Users
- B Equivalent Guardian Commands for OSS and UNIX Users
- C Equivalent Inspect Debugging Commands for dbx Commands
- D Equivalent Native Inspect Debugging Commands for dbx Commands
- E Standard POSIX Threads Functions: Differences Between the Previous and Current Standards
- Glossary
- Index
Porting UNIX Applications to the OSS Environment
Open System Services Porting Guide—520573-006
7-12
Function Prototypes
•
Do not assume that different pointer types are the same.
•
Use unsigned types for bit fields.
Function Prototypes
The ISO/ANSI C innovation of function prototypes is one of the more important
features added to the C language. Using proper function prototypes in header files
ensures that the invocation of a function from a program is compatible with the formal
definition of the function in terms of numbers and types of arguments, and the type of
the return value. In porting a Common C program to the OSS environment, you have
four options regarding the use of function prototypes:
1. Do nothing. The old code should compile.
2. Add function prototypes to just the headers. These prototypes cover all calls to
global functions.
3. Add function prototypes to the headers, and start each source file with prototypes
of its local functions.
4. Change all function declarations and definitions to use prototypes (either by
including the header files, which contain prototypes, or by explicitly defining
prototypes in source code files).
HP recommends using Option 4 to ensure that the program obeys the ISO/ANSI C
rules. However, all standard function prototypes have been added to the system
header files for the OSS environment, so there is a possibility that the program will
compile correctly using Option 1, provided that the proper system header files are
included in the program source files.
New programs should be written using the ISO/ANSI C standard. Programs written for
the OSS environment should also use the XPG4 specifications and the POSIX.1 and
POSIX.2 standards to maximize portability. Appropriate feature-test macros help you
check how well your program complies with these standards. The C header files
provided in the OSS environment contain definitions required by the ISO/ANSI C,
POSIX.1, and POSIX.2 standards, and by the XPG4 specifications. The visibility of
these definitions is controlled with feature-test macros.
If a program does not conform to the standard or specification controlled by a
feature-test macro such as _XOPEN_SOURCE, _XOPEN_SOURCE_EXTENDED, or
_TANDEM_SOURCE, the compiler issues error and warning messages. Feature-test
macros are discussed in the following subsection and in the C/C++ Programmer’s
Guide.
Defined Symbols and Header Files
All of the standard header files defined in the ISO/ANSI C, POSIX.1, and POSIX.2
standards and the XPG4 system interface specifications are supported in the OSS