Re: VPATH problem

[Philip Guenther]

On Sat, Feb 18, 2012 at 8:26 AM, Bgh Ello <address@hidden> wrote:
>      Greetings.  I am unable to get the simplest VPATH example working
> and could use some help.  I have a hello world program, hello.cpp in the
> src directory, and I can't reach it with VPATH.  Here is the makefile
...
> hello.o : hello.cpp
>         $(CC) $(OPTS) hello.cpp

In the GNU make docs, the page about VPATH has a link to another page
titled "Writing Recipes with Directory Search".  That page start with
this:
------
When a prerequisite is found in another directory through directory
search, this cannot change the recipe of the rule; they will execute as
written.  Therefore, you must write the recipe with care so that it
will look for the prerequisite in the directory where `make' finds it.

   This is done with the "automatic variables" such as `$^' (*note
Automatic Variables::).  For instance, the value of `$^' is a list of
all the prerequisites of the rule, including the names of the
directories in which they were found, and the value of `$@' is the
target.  Thus:

     foo.o : foo.c
             cc -c $(CFLAGS) $^ -o $@
------

There's more there, including an example for a .o target.


Philip Guenther