Re: SCM_LENGTH ???

[Ken Raeburn]

On Jan 10, 2005, at 12:26, Marius Vollmer wrote:
> The recommended way to check for deprecated features is to compile a
> version of Guile with --disable-deprecated and compile/link/test
> against that.

It might be a bit annoying to do in the source, but what about flagging 
deprecated symbols while still allowing their use, in the 
non-"--disable-deprecated" case?

E.g., declare a function SCM_LENGTH, which is declared in the header 
file with a macro which under recent enough versions of GCC expands to 
__attribute__((deprecated)) and on Windows to __declspec(deprecated), 
and in the source file defining the routine, on systems with the right 
compiler and assembler support, create a .gnu.warning.SCM_LENGTH (or 
.gnu.warning._SCM_LENGTH) section containing a message telling the user 
that the function will go away in a future release.  (As I understand 
it, on Windows you can even deprecate a macro by name.)

It won't work on all systems, but it should work on a lot of the 
configurations we'd care most about.  And if a macro is deprecated, the 
overhead of a function call shouldn't be a big deal, as long as the 
semantics are such that it can actually be implemented with a function 
call.

I started working out some configure tests and such to implement this 
at work, I could try to flesh them out a bit more if you like.  (I 
*think* I've got all my papers in order, but I don't know for sure if 
I've got papers in from my current employer, MIT, to cover Guile.  I 
haven't done the GNU maintainer bit in a while, could someone remind me 
where the list is?  Or check it for me?)

Ken