Option to turn down verbosity

[h-vetinari]

Make sure you completed the following tasks

• I searched the discussions
• I searched the closed and open issues

Found boostorg/build#348 which mentions:

[...] common.copy (which is in fact overly verbose when it comes to installing the headers. :-) )

Environment and version details

• Operating System+version: windows
• Compiler+version: MSVC
• Shell: Batch
• B2 Version: Bootstrapped from boost 1.82

Describe your use case

A default boost install will install about ~15000 headers. Each of those headers generates 3 lines of logs, à la:

common.copy %SRC_DIR%\temp_prefix\include\boost\type.hpp
%SRC_DIR%\boost\type.hpp
       1 file(s) copied.

This generates 10's of thousands of useless lines in the logs that make them unnecessarily hard to navigate.

Describe the solution you'd like

An option --quiet or --verbose=<level>

Alternatives, if applicable

...

Additional context

Stunned that this does not exist already (I tried looking in the docs & the internet, but didn't find anything).

[Kojoley]

I would also considered this a performance issue because currently virtual-targets.register is a huge bottle-neck, 3568793 out of 3687209 (96.8%) calls are to register these headers.

[grafikrobot]

There are two issues in this:

• Silencing the commands (and their output) for which we have -d0 .
• Having an action per file copy to do things like header file installs. For that there's this Optimize raw file copy action to coalesce into few copies. boostorg/build#454 old issue.

[pdimov]

I think that this is why I made --with-headers work, so that one can two-phase install as in

b2 -d0 --with-headers install
b2 install

[Kojoley]

I think 1 file(s) copied. output should be always suppressed (I have a PR for the same thing in tests #390).

copy action could be defined with quietly modifier like mkdir already does so common.copy ... lines will appear only with -d+2.