C/C++ Programmer's Guide (G06.27+, H06.03+)

Introduction to HP C and C++ for NonStop Systems
HP C/C++ Programmer’s Guide for NonStop Systems—429301-010
1-21
Following Good Programming Practices
Following Good Programming Practices
In general, the more you follow good programming practices, the easier it will be to port
your program to other hardware and software environments. A few of the most
important good programming practices are:
•
Use strictly conforming C language features as described in the ISO/ANSI C
standard as much as possible. Isolate HP defined and extended C language
features into specific modules.
•
Use function prototypes.
•
Place all environment-specific function declarations in a common header file, such
as environh.
•
Make sure the type of a function’s actual and formal parameters are the same.
•
Define every function with an explicit return type. Make sure the type of a return
expression is the same as the return type of the function.
•
Write your programs to a template similar to:
°
Feature-test macros
°
System headers
°
Local headers
°
Macros
°
File scope variables
°
External variables
°
External functions
°
Structures and unions
°
Signal-catching functions
°
Functions
°
Main function
•
Do not write code that relies on processor architecture. Be careful when writing
code that relies on word size, pointer size, bit fields, arithmetic precision, byte
order, stack size, stack growth, heap size, and heap growth.
•
Do not make assumptions about the size and format of any data type:
°
Use type short and type long instead of type int, if possible. In particular,
do not interchange between type int and type long.
°
Do not assign an int to or from a pointer without an explicit type cast.
°
Do not assume that different pointer types are the same.
•
Use unsigned types for bit fields.
There are many commercially available texts that describe how to write portable
applications in C, including: