Re: -V, --verbose, as opposite of -s, --silent, --quiet

[Alejandro Colomar (man-pages)]

Hello Paul, Dmitry, and David!

> On Sat, Oct 23, 2021 at 6:06 AM Paul Smith <psmith@gnu.org
> <mailto:psmith@gnu.org>> wrote:
>
>     On Sat, 2021-10-23 at 03:01 +0200, Alejandro Colomar (man-pages) 
wrote:
>      > I'd like a project to use '--silent' by default, to have readable
>      > output, and hide most of the full commands, which would be too
>      > noisy.
>      >
>      > So, ideally, I'd like to have 'MAKEFLAGS += --silent' in the
>      > Makefile.
>
>     Actually what you really want is the .SILENT special target.
>
> 
https://www.gnu.org/software/make/manual/html_node/Special-Targets.html#index-_002eSILENT
> 
<https://www.gnu.org/software/make/manual/html_node/Special-Targets.html#index-_002eSILENT>
>
>     That leads to this best-practice way to handle verbose output:
>
>     http://make.mad-scientist.net/managing-recipe-echoing/
>     <http://make.mad-scientist.net/managing-recipe-echoing/>
>
>

Hmm!  Yes, I knew about .SILENT, but didn't know about this usage of it. 
 It's interesting and simple enough, so I've started using it.

Since I use '--warn-undefined-variables', and also to help readability 
to someone who may not know about this usage and may wonder what does 
that $(V) mean, I used the following:

V :=
$(V).SILENT:

Thanks!


On 10/23/21 10:28 PM, David Boyce wrote:
> BTW we use a slightly different and, I think, slightly improved version 
> of what's shown there (see below). Improvements are:
>
> 1. Either the verbose or the concise output is shown, vs both in verbose 
> mode as the original does.

I thought about it, and I prefer printing both for the following reasons:

The verbose output tends to use many lines for each command, since it 
may easily use 500 characters per command.  Having a short line that 
uses uppercase at the beginning makes it much easier to know where each 
command starts.

Also, if you put that into a log file, then you can easily grep for the 
short line that you know you want to search, and next to it will be the 
long line (something like a dictionary).

And anyway, one short line per command (typically around 5-8 lines) 
won't hurt readability too much.

> 2. It uses $(info ...) instead of echo which saves a fork/exec per 
> recipe (note: this is safe only when used in the first recipe line).

Yup!  I also use $(info ...) since mad scientist showed it to me.  It 
made a huge impact in performance.

> 3. It provides a default "MAKING $@" message as demonstrated in the example.

Nah, I prefer explicit $(info ...) lines always.  Makes it easier to 
read, and also I prefer showing the command that runs every target.

Cheers,

Alex

> 4. A special case is used to ensure the clean target is always verbose.
>
> David
>
> $ cat Makefile
> .PHONY: all
> all: hola
>
> ifeq ($(V),)
>    vb = $(info $(or $1,MAKING $(@F)))
>    .SILENT:
> endif
>
> hola: hola.o
>          $(call vb)
>          $(CC) -o $@ $(LDFLAGS) $^ $(LDLIBS)
>
> %.o: %.c
>          $(call vb,CC $(<F) -> $(@F))
>          $(CC) -c -o $@ $(CPPFLAGS) $(CFLAGS) $<
>
> .PHONY: clean
> clean: clean_recipe = $(RM) *.o hola
> clean:
>          @$(info $(clean_recipe))
>          @$(clean_recipe)
>
>
> $ make clean; make
> rm -f *.o hola
> CC hola.c -> hola.o
> MAKING hola
>
> $ make clean; make V=1
> rm -f *.o hola
> cc -c -o hola.o   hola.c
> cc -o hola  hola.o
--
Alejandro Colomar
Linux man-pages comaintainer; https://www.kernel.org/doc/man-pages/
http://www.alejandro-colomar.es/