Help("""

  This is the second scons example. In this example we explore more options in
  scons. Once you start doing anything useful with scons other than showing
  how simple scons works, you will have to create an environment to have more 
  control on the build.
  
  One can "Dump()" the environment to see all the underlying details. We can 
  also compare between Linux and windows environments.

>> ls
foo.cpp  foo.hpp  main.cpp  SConstruct

>> scons
scons: Reading SConscript files ...
------------------>starting
------------------>ending
scons: done reading SConscript files.
scons: Building targets ...
g++ -o foo.o -c foo.cpp
g++ -o main.o -c main.cpp
g++ -o helloworld main.o foo.o
scons: done building targets.


>> ls -a
total 68
drwxr-xr-x 2 brgirgis users   154 Sep 26 23:04 ./
drwxr-xr-x 5 brgirgis users    36 Sep 26 22:44 ../
-rw-r--r-- 1 brgirgis users 21096 Sep 26 23:04 env.txt
-rw-r--r-- 1 brgirgis users    48 Sep 26 22:42 foo.cpp
-rw-r--r-- 1 brgirgis users   109 Sep 26 22:40 foo.hpp
-rw-r--r-- 1 brgirgis users  1256 Sep 26 23:03 foo.o
-rwxr-xr-x 1 brgirgis users 13288 Sep 26 23:03 helloworld*
-rw-r--r-- 1 brgirgis users   117 Sep 26 22:41 main.cpp
-rw-r--r-- 1 brgirgis users  2872 Sep 26 23:03 main.o
-rw-r--r-- 1 brgirgis users  2441 Sep 26 23:04 .sconsign.dblite
-rw-r--r-- 1 brgirgis users  1348 Sep 26 23:04 SConstruct


>> scons --tree=all helloworld
scons: Reading SConscript files ...
------------------>starting
------------------>ending
scons: done reading SConscript files.
scons: Building targets ...
scons: `helloworld' is up to date.
+-helloworld
  +-main.o
  | +-main.cpp
  | +-foo.hpp
  | +-/usr/bin/g++
  +-foo.o
  | +-foo.cpp
  | +-foo.hpp
  | +-/usr/bin/g++
  +-/usr/bin/g++
scons: done building targets.


""")

print('------------------>starting')
env = Environment()

open('env.txt', 'w').write(env.Dump())

env.Program(target='helloworld',
            source=['main.cpp', 'foo.cpp'])

print('------------------>ending')