all-makefiles-under v.s. first-makefiles-under

[Hylon]

Hi JBQ,

A title, any recommended using scenarios for below two functions? and
how about the pros and cons of them? thanks very much in advance. :)

all-makefiles-under v.s. first-makefiles-under

[Jean-Baptiste Queru]

I don't know. I didn't even know there was a "first-makefiles-under" function...

Ying, does this ring a bell?

JBQ

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Jean-Baptiste M. "JBQ" Queru
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[Ying Wang]

all-makefiles-under is defined as $(wildcard $(1)/*/Android.mk).

The builtin wildcard is quite efficient. So we should use $(call all-makefiles-under, $(LOCAL_PATH)) as you can.

 first-makefiles-under calls the script build/tools/findleaves.py to find Android.mks in the given directory.

If it finds an Android.mk in a directory, it just stops searching the subdirs.

It's not efficient, especially in case you have deep complex directory structure that does not have Android.mk in the top dirs.

We should use it as little as possible.

If your Android.mk's only purpose is to include all first-level sub-directory Android.mks, use:

include $(call all-subdir-makefiles)

If you want to include Android.mks in a specific set of first-level sub-directories:

include $(call all-named-subdir-makefiles, <subdirs>)

Those function names are really confusing.

Before using them please check their definitions in 
build/core/definitions.mk

[Ying Wang]

Both all-subdir-makefiles and all-named-subdir-makefiles use $(my-dir), which uses makefile's builtin MAKEFILE_LIST to get the current include chain of makefiles.

So they must be the called before any "include" statement in your makefile.

[Hylon]

Hi Ying & JBQ,
Thanks very much for your explanation.:)