scons env.InstallAs() doesn't seem to copy any file? - build

Question

For example, I've a .c file as below:
$cat hello.c
int main(){
return 0;
}
Then I use scons to build and copy it to some place:
$cat SConstruct
import os,sys
env = Environment()
hello = env.Program('hello.c')
env.InstallAs('/home/admin/hello-new', hello)
run scons under user named 'admin' it prints:
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
gcc -o hello.o -c hello.c
gcc -o hello hello.o
scons: done building targets.
Then I tried to "ls /home/admin" there's no such a thing like "hello-new". So I wonder why my "env.InstallAs()" worked at all? How to trouble-shoot and fix it?
Thanks.

Answer 1

Please read the FAQ, this is a common misunderstanding about SCons and thus in the FAQ:
https://scons.org/faq.html#How_do_I_install_files.3F_The_Install.28.29_method_doesn.27t_do_anything._In_general.2C_how_do_I_build_anything_outside_my_current_directory.3F
With your example changing to this should cause it to always build the target in question:
import os,sys
env = Environment()
hello = env.Program('hello.c')
install_target = env.InstallAs('/home/admin/hello-new', hello)
# Always build the install target by default
Default(install_target)