Re: Automatic Search for Object Files in the Link Stage

[Robert P. J. Day]

On Sun, 9 Jan 2005, Doron Bleiberg wrote:

> Hi,
> How can I link several object files which located under different
> directories to one executable ?
> For example, I want to call
> app: a.o b.o c.o
>       g++ a.o b.o c.o -o app
>
> a.o: ...
>
> and lets say that a.o is created locally (using the example make) while b.o
> and c.o are object files precompiled by other user and which located under
> different directory in the file system.
> I want the command: make app, to locate and link b.o and c.o automatically
> by searching predefined directory path. I don't want to copy manually all
> the needed objects before linking time.
> I know that I can use VPATH for the prerequisites, but how can I search for
> files in the Link stage ?

as i understand it, if you read

http://www.gnu.org/software/make/manual/html_chapter/make_4.html#SEC34

section 4.5.4, you'll see that, once VPATH takes care of *finding* the
prerequisites, you can refer to those prerequisites with respect to
their actual locations with the special variable "$^".  as it states:

  "the value of `$^' is a list of all the prerequisites of the rule,
  including the names of the directories in which they were found..."

so you would write:

app: a.o b.o c.o
        g++ $^ -o app


rday