Re: [Help-gsl] Compatibility with old and new inline functions in GSL

[Peter Johansson]

Hi Joseph,

On 5/27/10 1:32 PM, Joseph Wakeling wrote:
> The problem is, of course, an extension can't necessarily assume a
> particular version of GSL, so if I want it to be compatible with earlier
> versions I can't assume the presence of gsl_inline.h.
>
> So, this leads to the need to check for the version of GSL, and only if
> it is high enough to call #include<gsl/gsl_inline.h>; something along
> the lines of,
>
> #include<gsl_version.h>
> #if GSL_VERSION>= 1.13
> #include<gsl/gsl_inline.h>
> #else
> #define INLINE_FUN extern inline
> #endif
>
> ... except that since GSL_VERSION is actually a string "1.x" I'm not
> sure I can do the comparison.
>
> Is there any recommended procedure for dealing with this kind of version
> compatibility in GSL?
>
>    
This is a pefect use case for autoconf. Rather than checking which GSL 
version your client is using, you can implement a compilation test in 
your configure checking if 'gsl/gsl_inline.h' exists. If it exists 
define HAVE_GSL_INLINE and modify you preprocessor code to

#ifdef HAVE_GSL_INLINE
#include<gsl/gsl_inline.h>
#else
#define INLINE_FUN extern inline
#endif

If you need help with the autoconf syntax, please shoot an email.

Cheers,
Peter