Re: [Help-gsl] change in gsl_multifit_linear_svd

[Mohammad Akhlaghi]

On 09/21/2016 09:10 PM, Timothée Flutre wrote:

> Moreover, does someone know how I can use conditionals with the Autotools
> (via ./configure) so that, if the user has GSL <= 1.16, the compiled code
> uses gsl_multifit_linear_svd whereas if the user has GSL >= 2.0 the
> compiled code uses gsl_multifit_linear?

Once installed, GSL also installs an executable script called 
"gsl-config". If you run it with the "--version" option, this script 
will print the installed version of GSL:

$ gsl-config --version

You can use the output of this command, along with "AX_COMPARE_VERSION" 
(from the GNU Autoconf Archives) to check for the version. The link 
bellow shows how we do it in GNU Astronomy Utilities when we need to 
check the version of Ghostscript:

http://git.savannah.gnu.org/cgit/gnuastro.git/tree/configure.ac
(See the part that starts with the "Check Ghostscript:" comment)

You don't be needing the check on existance like our Ghostscript check, 
since I assume you will be using `AC_SEARCH_LIBS' for GSL's existance. 
You just need the indented part after `AC_MSG_CHECKING(Ghostscript 
version)'.

You can then pass the check's result into `config.h' and use the 
information in your programming to decide which function to use.

Cheers,
Mohammad