SConstruct

# SPDX-License-Identifier: MIT
#
# Copyright The SCons Foundation

def b(target, source, env):
    with open(target[0], 'wb') as f:
        f.write((env['X'] + '\n').encode())

DefaultEnvironment(tools=[])
env1 = Environment(X='111', tools=[])
env2 = Environment(X='222', tools=[])
B = Builder(action=b, env=env1, multi=1)
print("B =", B)
print("B.env =", B.env)
env1.Append(BUILDERS={'B': B})
env2.Append(BUILDERS={'B': B})
env3 = env1.Clone(X='333')
print("env1 =", env1)
print("env2 =", env2)
print("env3 =", env3)
f1 = env1.B(File('file1.out'), [])
f2 = env2.B('file2.out', [])
f3 = env3.B('file3.out', [])

def do_nothing(env, target, source):
    pass

AddPreAction(f2[0], do_nothing)
AddPostAction(f3[0], do_nothing)
print("f1[0].builder =", f1[0].builder)
print("f2[0].builder =", f2[0].builder)
print("f3[0].builder =", f3[0].builder)
print("f1[0].env =", f1[0].env)
print("f2[0].env =", f2[0].env)
print("f3[0].env =", f3[0].env)