C/C++ Programmer's Guide (G06.27+, H06.08+, J06.03+)

The C compiler running in the OSS environment supports only the large-memory model and ILP32
data model.
The memory model and data model selected determines the model-dependent library file that you
bind into a program. For more details, see Chapter 14: Compiling, Binding, and Accelerating
TNS C Programs, and Chapter 15: Compiling, Binding, and Accelerating TNS C++ Programs.
Converting Programs to the ILP32 Data Model
HP strongly recommends that you convert your TNS C and C++ programs from the 16-bit data
model to the ILP32 (or wide) data model. The native C and C++ compilers do not support the
16-bit data model. This list provides guidelines for this conversion using the TNS C compiler and
Cfront:
• Compile your program using the STRICT pragma.
• Ensure that the type of a function call argument matches the defined type of its associated
parameter. The compiler issues this warning message for argument-parameter mismatches:
Warning 86: argument "name" conflicts with formal definition
• Write function prototypes for all user-written functions that don’t have prototypes. The compiler
issues this warning message for function calls that don’t have corresponding function prototypes:
Warning 95: prototype function declaration not in scope: "function-name"
• Ensure that the formal and actual parameters of pointer types are matched. The compiler issues
this warning message if pointers do not match:
Warning 30: pointers do not point to same type of object
For example:
int func1(short *);
In the 16-bit data model and the large-memory model, you can pass to func1 a pointer of
type short or int and get the correct results. In the ILP32 data model, you can pass to
func1 only a pointer of type short; a pointer of type int generates incorrect results.
Parameter mismatch is most often an issue for Guardian system procedures and external TAL
routines.
• Ensure that literals do not cause type mismatches.
#include <cextdecs(MONITORCPUS)>
...
short get_cpu_number;
MONITORCPUS(0x8000 >> get_cpu_number);
In the ILP32 data model, if get_cpu_number is equal to zero, an arithmetic overflow occurs
because the compiler generates code to convert an unsigned 32-bit integer to a 16-bit signed
integer. Note that cextdecs does not use the type unsigned short.
• Avoid using the type int in your program, if possible. Use type long or short instead.
However, if you want to keep your program data-model independent, you cannot avoid using
type int completely. For example, C library calls, bit-fields, TCP/IP sockets library functions,
and Guardian system procedures might require type int.
Debugging C and C++ Programs
To debug C and C++ programs, you can use several debuggers:
• Debug on TNS/R systems
• Inspect on TNS/R or TNS/E systems
• Native Inspect on TNS/E systems and from within NSDEE on the PC
• The Visual Inspect debugger
326 Running and Debugging C and C++ Programs