Hi Bob, * Bob Friesenhahn wrote on Wed, Dec 10, 2008 at 04:04:23PM CET: > On Wed, 10 Dec 2008, Tom Browder wrote: >>> * Tom Browder wrote on Wed, Dec 10, 2008 at 01:38:53AM CET: >>>> Is it "legal" to use the "+=" operator in lieu of "\" when listing >>>> members of a variable in Makefile.am's? >>> >>> Yes. In this case, an Automake extension over portable make syntax, >>> i.e., automake will flatten the += and 'make' won't ever see it. > > I didn't really trust += in my own Automake makefiles since it was not > really clear to me in what order the appending would occur and since I > am also using Automake includes, the ordering might get changed in some > bad way if the include order is changed. So for my makefiles I used > additional variables with explicit concatenation, leaving nothing to > chance.
With +=, the order is kept as you specify it. Even with conditionals in the loop, as in foo = a if COND foo += b else foo += c d endif foo += e There used to be issues in this area, but they have been fixed for quite some time (see NEWS if you need details). Cheers, Ralf