Passing variables from include directive to sub-make

Question

Looking for some help passing variables from one level to the next in a makefile. I have a source tree that needs to be built to run on various target architectures. To keep the higher level makefile clean I created separate makefiles that contain architecture specific information and include only the one that is required using the include directive :) Later in the makefile I transfer to another directory to build the source files. The build fails and I see that the failure is caused by the architecture-specific variables not being passed. ``` ifeq ($(ARCH), my_arch) | include build/my_archdefs.mk | section 1 endif | <more commands> debug: $(MAKE) -C src debug ``` The makefile to build the code tree is in the src directory. As a stop gap measure I included section 1 referenced above in the lower level makefile and in this case I noticed that the variable ARCH was not being passed down. Here are a couple of links I found that seemed related but I'm not able to figure out what I need to…

Accepted Answer

This link should help: http://www.gnu.org/software/make/manual/html_node/Variables_002fRecursion.html#Variables_002fRecursion

In your top level Makefile just add the line `export` and all of your variables will be exported to your submakes.

Example:

File `Makefile`:

```
ID=asdf
export
all:
    @echo ${ID}
    @make -f Makefile2
```

File `Makefile2`:

```
all:
    @echo ${ID}
```

Output:

```
$ make
asdf
make[1]: Entering directory `/home/user/Desktop/a'
asdf
make[1]: Leaving directory `/home/user/Desktop/a'
```

Passing variables from include directive to sub-make

Solution

Problem