Re: gmake feature (enhancement)

[Paul Smith]

On Wed, 2018-01-24 at 12:46 +0100, Phi Debian wrote:
> 1) I'd like that -jN do leave some foot print in the environment, OR
> better set a gmake internal variable (predefined name) with the number
> that as given.

> 2) I'd like o suppress the enter/leaving message.
> make: Entering directory '...'
> make: Leaving directory '...'

The answer to both your questions is the MAKEFLAGS variable (although
for the first one you need GNU make 4.2 or higher).

https://www.gnu.org/software/make/manual/html_node/Options_002fRecursion.html

The amount of -j is available in MAKEFLAGS; with no -j:

  $ echo 'all:;$(info MAKEFLAGS is $(MAKEFLAGS))' | make -f-
  MAKEFLAGS is 

With some -j:

  $ echo 'all:;$(info MAKEFLAGS is $(MAKEFLAGS))' | make -f- -j5
  MAKEFLAGS is  -j5 --jobserver-auth=3,4

(ignore the jobserver option).  So you can use something like:

  $ echo 'all:;$(info -j is $(patsubst -j%,%,$(filter
-j%,$(MAKEFLAGS))))' | make -f-
  -j is 

  $ echo 'all:;$(info -j is $(patsubst -j%,%,$(filter -j%,$(MAKEFLAGS))))' | 
make -f- -j5
  -j is 5

For suppressing enter/leave messages, you can just add --no-print-
directory to MAKEFLAGS yourself, for example in the makefile:

  $ cat Makefile
  all: ; $(MAKE) recurse
  recurse: ; : recurse

  $ make
  make recurse
  make[1]: Entering directory '/tmp'
  : recurse
  make[1]: Leaving directory '/tmp'

Now try:

  $ cat Makefile
  MAKEFLAGS += --no-print-directory
  all: ; $(MAKE) recurse
  recurse: ; : recurse

  $ make 
  make recurse
  : recurse