TNS/E Native Application Conversion Guide
C and C++ Conversion Tasks
TNS/E Native Application Conversion Guide—529659-003
3-4
Converting Code to Use 32-Bit Pointers and Integers
•
Ensure that the type of a function call argument matches the defined type of its
associated parameter. The TNS C 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 without prototypes. The TNS
C compiler issues this warning message for function calls without 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
TNS C 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 correct results. In the 32-bit 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 and pTAL procedures.
•
Ensure that literals do not cause type mismatches, as illustrated in this example:
#include <cextdecs(MONITORCPUS)>
...
short get_cpu_number;
MONITORCPUS(0x8000 >> get_cpu_number);
In the 32-bit 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. Declarations in the cextdecs header file
do 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.