Question

I have a Hierarchical project that uses source code from a common system-directory, for which I am using the SCons Repository() function and want all the build output (local code and code taken from the Repository) placed in a variant_dir.

If I use the Repository() function in a simple scenario (non-hierchical with no calls to sub-directory SConscripts) then the compiled Repository() object file is placed in the variant_dir as expected. But if I do the same in a hierarchical build, the compiled Repository() object file is placed in the project root directory.

Assuming I want to use the following source code located in a system-directory:

/usr/local/repoDir/repoFile.cc

And I have the following project structure:

# tree .
.
|-- SConstruct
|-- build
|   `-- linux_x86_64
`-- moduleA
    |-- localFile.cc
    `-- SConscript

Here are the build scripts:

SConstruct

Edit: Removed filename from call to Repository(), thanks to Dirk Baechle from [e-mail] for pointing that out.

env = Environment()

env.Repository('/usr/local/repoDir')

env['variantDir'] = 'build/linux_x86_64'

SConscript('moduleA/SConscript',
           exports = ['env'],
           variant_dir = env['variantDir'],
           duplicate = 0)

moduleA/SConscript

import os

Import('env')

srcFiles = [
  'localFile.cc',
  #os.path.join(env['variantDir'], 'repoFile.cc'),          # fails to find source file
  #'#%s' % os.path.join(env['variantDir'], 'repoFile.cc'),  # fails to find source file
  #'repoFile.cc',                                           # fails to find source file
  '#repoFile.cc',  # only option that works, but places object in root proj dir
]

env.Append(CPPPATH = ['.', '#'])
env.Program(target = 'myApp', source = srcFiles)

I would like the repoFile.cc file to be compiled and have its object file placed in build/linux_x86_64, but instead its placed in the same directory as the root SConstruct.

As you can see from the comments in moduleA/SConscript, I tried referencing the repoFile.cc several different ways, and the only way that worked is as mentioned therein. Additionally, I tried calling the Repository() function in moduleA/SConscript, but it didnt change anything.

Edit: Here is the compilation output

# scons
scons: Reading SConscript files ...
scons: done reading SConscript files.
scons: Building targets ...
g++ -o repoFile.o -c -Ibuild/linux_x86_64 -ImoduleA -I/usr/local/repoDir/moduleA -I/usr/local/repoDir/build/linux_x86_64 -I. -I/usr/local/repoDir /usr/local/repoDir/repoFile.cc
g++ -o build/linux_x86_64/localFile.o -c -Ibuild/linux_x86_64 -ImoduleA -I/usr/local/repoDir/moduleA -I/usr/local/repoDir/build/linux_x86_64 -I. -I/usr/local/repoDir moduleA/localFile.cpp
g++ -o build/linux_x86_64/myApp build/linux_x86_64/localFile.o repoFile.o
scons: done building targets.

And resulting directory structure:

# tree .
.
|-- repoFile.o    <=== This file should be in build/linux_x86_64 NOT here
|-- SConstruct
|-- build
|   `-- linux_x86_64
|       |-- localFile.o
|       `-- myApp
`-- moduleA
    |-- localFile.cpp
    `-- SConscript

I checked around and found this, but its not quite the same:

Scons Hierarchical Builds with Repository directory

Any suggestions as to how I can get the object file in the right place?

Answer 1

I asked this same question on the SCons-users mailing list, and received some information that partly answers this question. Thanks to Dirk Baechle for helping me with this issue.

The Repository() function effectively mounts the directory passed in to the root of the SCons project: that is to the directory where the SConstruct file is. If files in a repo sub-directory need to be referenced in sub-directories of the SCons project, then the sub-directory names (that of the repo dir and scons project dir) must match. That’s why the different options in the SConscript file in the question above fail to find the repo file.

If the repo sub-directory moduleA existed with the file repoFile.cc, then it would be found as expected and the compiled object would be placed in the variant_dir as expected.

One limitation I see to the Repository() function is that you can’t mount the repo directory to a SCons project sub-directory. This sounds like a feature request.

The fact that SCons places the compiled object file in the source directory seems like a bug to me. At the very least, it should be placed in the variant_dir root directory.