[Info-vax] DEC C 64/32 bit pointer conversion question

[John E. Malmberg]

On 9/13/2019 3:37 PM, Arne Vajhøj wrote:
> Can you provide a two module example showing the problem?

I found out what I was doing wrong.

And I was looking at the wrong value in the debugger.  The value was 
something like 80000020

A 32 bit pointer on VMS is actually only 31 bits, not 32 bits.

Adjusting the code to handle that case results in:


#pragma pointer_size save
#pragma pointer_size 64
   typedef char * char_ptr64;
#pragma pointer_size 32
   typedef char * char_ptr32;
#pragma pointer_size restore

static void
convert32 (const char * str, char_ptr32 * str32)
{
     int len32;
     char_ptr32 new_str32;

     /* Only copy the pointer if it is larger than 32 bits */
     if (((unsigned long int)str & 0xFFFFFFFF80000000) == 0)
       {
         *str32 = (char_ptr32)((unsigned)str & 0x7FFFFFFF);
       }
}

Regards,
-John