G'Day Paul,
 
-=> Quoting Paul Wankadia to Frank Adam <=-

 PW> What would I have to do?  Use strdup() to duplicate the string locally
 PW> and then sizeof() that duplicate string perhaps???
Shivers. Alloc(), strcpy(),sizeof(), and free() just to find the byte 
length ? 
I'm not sure if it'll work anyway, i think it just copies strlen(string).

Best way is to just send the old fashioned maxsize to the function, the 
string may not always be allocated just for the input anyway.
Eg. What happens if..

char* GetString(char *s)
{
 ...
 size = GetSize(s);
  /* beuty, we can get (size - 1) chars if the user is willing. */
 /* ... */   
 return s; /* let's say user entered 92 chars.*/
 };

int main()
{
 char mystr [100];  /* frank's line */
 GetString(mystr);
 strcat(mystr," - said Frank."); /* oh-oh 92+15 = buckle_up */
 return 0; 
 }

Ok, then i would have to make sure in the calling function that the 
returned string is big enough to manipulate further. 

int main()
{
 char mystr [100];  /* frank's line */
 GetString(mystr);
 if(GetSize(mystr)) > (100 - 16) ) /* did he rumble on again ? */
  printf("out of string length"); 
 else
  strcat(mystr," - said Frank.");  
 return 0; 
 }

Now i've saved a sizeof(mystr) to send, but lost a sizeof call and an 
if else statement on return, not to mention the extra work the getstr() 
function had to do.                      
I know what you're trying to do, i worked on the same thing few months 
back, that's exactly what made me do that function with heapwalk().
It's good fun, but i haven't used that code since. 
                         
 PW> BTW how can I make a pointer to point to a set place in memory (i.e.
 PW> segment and offset) ???
Take a look at MK_FP(), and also FP_OFF(),FP_SEG().
 
char far *x;
x = (char far*) MK_FP( (unsigned) seg, (unsigned) off );
if you know the actual address.
or..
x = (char far*) MK_FP( FP_SEG(var) , FP_OFF(var) );                        
C++ may also want a cast to unsigned on FP_SEG/OFF.
Btw MK_FP(), is not ISO, but there is a portable replacement in SNIPPETS.
Or you can always swipe VidMgr's #define for it, it looks close.:-)                 
                                                                
 FA> Perhaps if the string is global it may also work, but i didn't try or
 FA> even said that !.:)
 PW> What's wrong with global variables? :)
Nothing when used in moderation, that was just a preemptive strike in 
case i was wrong..:)
                               
 FA> PS: if portability is not an issue look at heapwalk in Borland, or go
 PW> What does heapwalk() do?  (Forgive all these questions -- I only got
Heapwalk goes through the internal allocation table, and report the number 
of bytes allocated to each variable and the state of the memory.
With a bit of coding it can return the REAL size of any variable.
I've posted a piece of code here few months back on that, but i can't 
seem to find it just now.
Anyway it doesn't matter 'cause it was deemed to be highly non portable.

 FA> alloced block size somewhere, it only seems to work with the Borland
 FA> RTL..
 PW> What's RTL?  BTW I'd rather keep the code as portable as possible
 PW> (between PC compilers anyway), so that's not an option really...
Run Time Library. 
                  
WRT to the other mssg, an M3 is a BMW, a car that is :-)

  L8r Frank (fadam{at}ozemail.com.au).
                                                 
___ Blue Wave/DOS v2.21

--- Gash