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

System-Level Programming
HP C/C++ Programmer’s Guide for NonStop Systems—429301-010
9-3
Passing Pointers to Constants Between Code
Spaces
Example
This example shows valid uses of the CSADDR pragma to pass pointers to constants
between code spaces:
#pragma env library
#pragma csaddr
#pragma xmem
void foo( const void * );
main()
{
const struct S { int i,j,k; } s = { 10, 20, 30 };
const struct S *sp;
foo( "This is a test" ); /* 15 bytes copied and passed */
foo( &s ); /* 6 bytes copied and passed */
sp = &s;
A pointer variable to the code space cannot be initialized. Explicit assignment or
conversion to array type is recommended. For example, this function results in an
error because name is an array of pointers and therefore cannot be initialized:
#pragma env library
#include <stringh>
int find_kevin(void)
{
const char *name[] =
{"linda", "don", "kevin"};
const int LAST_NAME = 3;
const char *p;
int i = 0;
for (p = name; i <= LAST_NAME ; i++, p = &name[i])
if (!strcmp(p, "kevin"))
return TRUE;
return FALSE;
}
The previous function can be made valid by converting name to a two dimensional
array without making any other changes, as shown in this code:
#pragma env library
#pragma inline
#include <stringh>
int find_kevin(void)
{
const char name[][6] =
{{"linda"}, {"don"}, {"kevin"}};
const int LAST_NAME = 3;
const char *p;
int i = 0;