[Ecls-list] compiler flags for external libraries

[Juan Jose Garcia-Ripoll]

On Saturday 22 November 2003 03:08, Robert Lehr wrote:
> First, has it been done with ECL?  If so, what is the usual method?  I
> accomplished this by modifying the exported c:*cc*.

Don't do it this way. I do not remember whether it was introduced in ECL 0.9c, 
but the right way would be to use
	C::BUILD-FASL
It works just like BUILD-PROGRAM, but builds a loadable module. Another 
possibility would be to just rebind c:*ld-bundle-flags* (in CVS) or 
c:*ld-flags* (in previous versions), prepending your flags. As of writing 
this message I realized that neither of these options is nice, and I will 
probably add another argument to COMPILE-FILE or COMPILE so that users can 
supply their own ld- and cc- flags.

> The second matter concerns current scope during compilation.  These two
> forms fail...
>
> (eval-when (:compile-toplevel)
>   (in-package :c)
>   (setq *cc*
> 	(format nil "~A ~A" *cc*
> 		" -I/usr/include/my-lib -Wl,-L/usr/lib/mylib -Wl,-lmylib")))
> That does not seem right to me.  Is that correct?  If so then then why?

Yes, _ECL_ is right :-) The whole eval-when is read together, because it is a 
single list. That means that your (in-package :c) does not take place when 
the form is read, but afterwards, at run time, and the symbol *cc* is read in 
the cl-user package, not in the C package. The right way to code that:

(eval-when (:compile-toplevel)
  (setq c::*cc*
        (format nil "~A ~A" *cc*
                " -I/usr/include/my-lib -Wl,-L/usr/lib/mylib -Wl,-lmylib")))

But this is also not "right". If you want to change the compiler or linker 
flags, do it around your compilation form:

	(let ((c::*cc-flags* (concatenate 'string c::*cc-flags* "..."))
	      (c::*ld-bundle-flags* (concatenate ...))
	      ...)
	   (compile ...))

or define your own compile-file function which wraps around the original one.

	(let ((old-cf #'compile-file))
	   (si::package-lock "CL" nil) ;; So that ECL does not complain
	   (defun compile-file (&rest args)
	      (let ((c::*cc-flags* ...)
		    ...)
		(apply old-cf args))))

Regards,

Juanjo