Once a program is built,
it is often appropriate to install it in another
directory for public use.
You use the &Install; method
to arrange for a program, or any other file,
to be copied into a destination directory:
env = Environment()
hello = env.Program('hello.c')
env.Install('__ROOT__/usr/bin', hello)
int main() { printf("Hello, world!\n"); }
Note, however, that installing a file is
still considered a type of file "build."
This is important when you remember that
the default behavior of &SCons; is
to build files in or below the current directory.
If, as in the example above,
you are installing files in a directory
outside of the top-level &SConstruct; file's directory tree,
you must specify that directory
(or a higher directory, such as /)
for it to install anything there:
scons -Q
scons -Q __ROOT__/usr/bin
It can, however, be cumbersome to remember
(and type) the specific destination directory
in which the program (or any other file)
should be installed.
This is an area where the &Alias;
function comes in handy,
allowing you, for example,
to create a pseudo-target named install
that can expand to the specified destination directory:
env = Environment()
hello = env.Program('hello.c')
env.Install('__ROOT__/usr/bin', hello)
env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }
This then yields the more natural
ability to install the program
in its destination as follows:
scons -Q
scons -Q install
Installing Multiple Files in a Directory
You can install multiple files into a directory
simply by calling the &Install; function multiple times:
env = Environment()
hello = env.Program('hello.c')
goodbye = env.Program('goodbye.c')
env.Install('__ROOT__/usr/bin', hello)
env.Install('__ROOT__/usr/bin', goodbye)
env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }
int main() { printf("Goodbye, world!\n"); }
Or, more succinctly, listing the multiple input
files in a list
(just like you can do with any other builder):
env = Environment()
hello = env.Program('hello.c')
goodbye = env.Program('goodbye.c')
env.Install('__ROOT__/usr/bin', [hello, goodbye])
env.Alias('install', '__ROOT__/usr/bin')
Either of these two examples yields:
scons -Q install
Installing a File Under a Different Name
The &Install; method preserves the name
of the file when it is copied into the
destination directory.
If you need to change the name of the file
when you copy it, use the &InstallAs; function:
env = Environment()
hello = env.Program('hello.c')
env.InstallAs('__ROOT__/usr/bin/hello-new', hello)
env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }
This installs the hello
program with the name hello-new
as follows:
scons -Q install
Installing Multiple Files Under Different Names
Lastly, if you have multiple files that all
need to be installed with different file names,
you can either call the &InstallAs; function
multiple times, or as a shorthand,
you can supply same-length lists
for both the target and source arguments:
env = Environment()
hello = env.Program('hello.c')
goodbye = env.Program('goodbye.c')
env.InstallAs(['__ROOT__/usr/bin/hello-new',
'__ROOT__/usr/bin/goodbye-new'],
[hello, goodbye])
env.Alias('install', '__ROOT__/usr/bin')
int main() { printf("Hello, world!\n"); }
int main() { printf("Goodbye, world!\n"); }
In this case, the &InstallAs; function
loops through both lists simultaneously,
and copies each source file into its corresponding
target file name:
scons -Q install