[clug] linking makefiles

[David Tulloh]

You can either do it in a single makefile or in multiple files.
If you are only looking at linking in a few files then I think a single
file is far simpler.

For a single makefile you just need:
file: file.o ../A/i2c.o
../A/i2c.o: ../A/i2c.c ../A/i2c.h

If you had several you wanted to link in you can use a second makefile
to nicely group the dependancies.
A/Makefile
i2c.o: i2c.c i2c.h

B/Makefile
file: file.o ../A/i2c.o
../A/%.o:
        make -C ../A $@

Both of these use implicit rules to do all the work.

deepshikha wrote:
> hello,
>  i am having a problem compiling a C code. i have two directories and each 
> one has a separate Makefile.
> a program(file.c) in directory 'B' needs to access a function which belongs 
> to a file(i2c.c, i2c.h) in directory 'A'. 
>  how do i link the two files. will i have to make a new makefile?
>  will appreciate any kind of help.
>  thanks