Re: How to write an elegant makefile with -fprofile-generate and -fprofile-use ?

[Martin d Anjou]

> So, I'm looking for an idea to compile twice the same program (with the
> same .o) with different option.

You could use as command line variable (see Overriding Variables in the 
make manual). Suppose you compile with this rule:

toto.o: toto.c
        $(COMPILER) $(MY_OPT) toto.c -ouput toto.o

Then from the command line you can call it with either:
  make MY_OPT=-fprofile-generate
or:
  make MY_OPT=-fprofile-use
or nothing at all:
  make

If you do not specify MY_OPT, make will put a blank for $(MY_OPT). It will 
not complain that it is undefined (see -warn-undefined-variables in the 
make manual).

Please ignore that I do not know how to compile C programs and that the 
-output switch is probably wrong. My point is to use MY_OPT as a command 
line variable to show you one way of doing what you want. There are other 
ways, but this is the first that comes to my mind.

HTH,
Martin