RE: [GD-Windows] Function to see if a pointer is on the stack

[Jacob T. \(C. D. Ltd\) <Ja...@Co...>]

Unfortunately can't do the reliable method.  My example for copying =
strings is just an example so can't use std::string<> or bare pointer =
technique.

Bit scared about the other option because we are in a multi-threaded app =
and this function would be common to all threads and we don't have =
explicit creation of common library stuff when a new thread is made.

Isn't there a really PC specific code e.g. getting the stack ptr etc.  =
This is how I am doing the function on consoles.

Mind you not a big hassle because on the PC we have so much memory that =
don't care if just always copy strings or whatever data i.e. can make is =
variable on stack function return TRUE all the time.

Thanks

Jake

> -----Original Message-----
> From: gam...@li...
> [mailto:gam...@li...]On Behalf Of
> Jon Watte
> Sent: 19 August 2004 18:19
> To: gam...@li...
> Subject: RE: [GD-Windows] Function to see if a pointer is on the stack
>=20
>=20
> The most reliable way of doing this is to use a class for
> your argument rather than bare pointers, and have a
> constructor from bare pointers, and use reference counting
> in the class implementation -- this is almost exactly what
> std::string<> already does for you!
>=20
> Else, you can register the stack pointer in main() (or the
> entry function for each thread/fiber), and get the stack
> pointer in the called function, and compare -- this is not
> entirely portable, because the stack may grow up on some
> architectures.
>=20
> // non-threaded version -- if you use threads or fibers,
> // you need one gBase per thread/fiber
>=20
> char * gBase;
>=20
> void register_main( char * base ) {
>   gBase =3D base;
> }
>=20
> bool is_stack_pointer( char const * ptr ) {
>   char top[10];
>   assert( top < gBase ); // else stack grows up
>   return (ptr < gBase) && (ptr > top);
> }
>=20
> int main() {
>   ...
>   char junk[ 10 ];
>   register_main( junk );
>   ...
> }
>=20
> void some_func( char * anArg ) {
>   if( is_stack_pointer( anArg ) ) {
>     ...
>   }
> }
>=20
>=20
> -----Original Message-----
> From: gam...@li...
> [mailto:gam...@li...]On Behalf Of
> Jacob Turner (Core Design Ltd)
> Sent: Thursday, August 19, 2004 9:30 AM
> To: gam...@li...
> Subject: [GD-Windows] Function to see if a pointer is on the stack
>=20
>=20
> Is there some simple and reliable code for a console or=20
> windows app to test
> if a pointer value is on the stack or not ?
>=20
> If the pointer is on the stack (e.g. a string) then we want=20
> to copy the
> string to heap memory for reuse later on.
>=20
> Cheers
>=20
> Jake
>=20
>=20
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