Difference between bjam install and stage

From: Edward Diener (eddielee_at_[hidden])
Date: 2005-07-19 14:35:32

The documentation for building Boost states that one can use 'install', 'stage', 
or nothing on the bjam command line. But it does not explain the difference 
between these options other than:

"none Only builds the Boost libraries. This lets you do the first part of what 
the install action normally does without copying the built libraries to the 
install location.

install Builds and installs Boost libraries and headers.

stage Builds the Boost libraries and copies them into a common directory."

This tells me almost nothing. In the 'none' explanation, what does "copying the 
built libraries to the install location" mean when the install location is never 
specified ? In the 'install' explanation, what does "installs Boost libraries 
and headers" mean and why do headers need to be installed ? In the 'stage' 
explanation, what is the "common directory" to which Boost libraries are copied 
? In general where exactly are resulting libraries put for each of these options 
and are header files moved anywhere also ?