Re: @....@ how does it work ?

[Jean Bréfort <jean brefort normalesup org>]

Le vendredi 09 septembre 2005 �0:05 +1000, Rod Butcher a �it :
> Can somebody explain or point me to some documentation on what's going 
> on with lines like :-
> CFLAGS = @CFLAGS@
> in my Makefile.in (built via glade & then automake) which then gets 
> translated into :-
> CFLAGS = -g -O2
> by configure.
> So how/where from does @CFLAGS@ become -g -O2 (medium-optimised) ?
> My test program works OK, but I want to know what's going on in the 
> configure. I have the Goat Book text but can't find the @...@  bit. I 
> presume it's a substitution, but from where ?

There is a call to AC_SUBST in configure.in:
AC_SUBST(CFLAGS)

If you use any variable:
MY_VAR="some value"
AC_SUBST(MY_VAR)

you can use @MY_VAR@ in Makefile.am or some .in files such as
my_program.pc.in. configure will replace with the value.