Find out target platform of build? - scons

How do I find out what platform SCons is building for (Linux, Mac OS X, Windows, &c-- not concerned with architecture).

You can also use env['PLATFORM'] once you've created an Environment. I think it comes from sys.platform.

Will http://docs.python.org/library/platform.html#platform.platform (true,true)
do what you want? If not you may have to map it yourself from data in the other
platform methods.

Scons has a builtin function Platform() that you can call before you create your Environment. Probably preferable to use Platform() than Python's platform.platform(true, true) (you don't have to import platform into you SConstruct, for example.) After you've created your environment you should use env['PLATFORM'] as suggested by #GaryO.

Related

Different versions of compilers + libgcc on windows encountered

I have a third-party library which depends on libgcc_s_sjlj-1.dll.
My own program is compiled under MSYS2 (mingw-w64) and it depends on libgcc_s_dw2-1.dll.
Please note that the third-party library is pure binaries (no source). Please also note that both libgcc_s_sjlj-1.dll and libgcc_s_dw2-1.dll are 32-bit, so I don't think it's an issue related to architecture.
The outcome is apparent, programs compiled based on libgcc_s_dw2-1.dll can't work with third-party libraries based on libgcc_s_sjlj-1.dll. What I get is a missing entrypoint __gxx_personality_sj0.
I can definitely try to adapt my toolchain to align with the third-party's libgcc_s_sjlj-1.dll, but I do not know how much effort I need to go about doing it. I find no such variant of libgcc dll under MSYS2 using this setjmp/longjmp version. I am even afraid that I need to eliminate the entire toolchain because all the binaries I had under MSYS2 sits atop this libgcc_s_dw2-1.dll module.
My goal is straightforward: I would like to find a solution so that my code will sit on top of libgcc_s_sjlj-1.dll instead of libgcc_s_dw2-1.dll. But I don't know if I am asking a stupid question simply because this is just not possible.
The terms dw2 and sjlj refer to two different types of exception handling that GCC can use on Windows. I don't know the details, but I wouldn't try to link binaries using the different types. Since MSYS2 does not provide an sjlj toolchain, you'll have to find one somewhere else. I would recommend downloading one from the "MingW-W64-builds" project, which you can find listed on this page:
https://mingw-w64.org/doku.php/download
You could use MSYS2 as a Bash shell but you can probably not link to any of its libraries in your program; you would need to recompile all libraries yourself (except for this closed source third-party one).

Rcpp functions delivery

I have made some Rcpp functions for some on-going work, but the work may be performed my colleagues who are R beginners. My question is, if my colleagues want to use these function on their machines, do they have to install Rtools and use sourceRcpp() to compile the functions first? Is that any way I can avoid this? For example, use the function just like using require()?
Thanks.
On any OS, R permits you to provide a binary package. On Windows and OS X, this is even common. You did not (explicitly) state what OS your colleagues use; from context (Rtools?) it is presumably Windows. You could even use the win-builder service to compile it.
This is very basic packaging question, which is addressed in the Writing R Extensions manual. There is nothing particular about Rcpp here.
We do however have an entire vignette on packaging which you should read, and the material is also covered in the Rcpp book.

Linux/Mac: What is good method to determine platform at compile time?

I would like to generalize a build system to compile on several (somewhat similar) platforms. What is a good method for determining the type of host that the shell script or Makefile is running on. I would like to distinguish between mac and linux, but also different specific distributions of linux (e.g. RHEL, Ubuntu). Cygwin is not important for me, but if you include it in your response I am sure others will find it valuable.
The rationale may include using the host type to fetch and install the correct versions of binary packages when it is more convenient to do so than compile from source. In addition, some commercial software is binary-packaged for specific distros, so part of the motivation is to grab the right binary.
Thanks,
SetJmp
Autotools to the rescue. It has tons of macros that help you do this kind of stuff.
http://www.lrde.epita.fr/~adl/autotools.html
uname -a to distinguish major *nix variants
Not so sure what the best way to distinguish red hat from ubuntu would be - could look for package managing tools and query installed packages, eventually helping you narrow down different debian derivatives, etc. There's probably something more obvious and up front though.
linux variants generally store distro information in /etc/issue.
most kernels will put info in /proc/version
It's not completely straightforward. You can use uname to find out the general parameters but to differentiate between distributions is a harder task. Maybe you should consider using something like autoconf to generalise your build system?
Just in case you're using Qt, there's this really nice set of defines, Q_OS_*, that guide you to the Operating System you're compiling on:
Q_OS_AIX
Q_OS_BSD4
Q_OS_BSDI
Q_OS_CYGWIN
Q_OS_DARWIN
Q_OS_DGUX
Q_OS_DYNIX
Q_OS_FREEBSD
Q_OS_HPUX
Q_OS_HURD
Q_OS_IRIX
Q_OS_LINUX
Q_OS_LYNX
Q_OS_MAC
Q_OS_MSDOS
Q_OS_NETBSD
Q_OS_OS2
Q_OS_OPENBSD
Q_OS_OS2EMX
Q_OS_OSF
...
They are defined in QtGlobal. There are even defines that help you figure out the compiler used Q_CC_* or the target Windowing System Q_WS_*.
But if you're not using Qt and want to go for a generic method, you most likely have to fall back to the Autotools package or CMake.
Determining Linux distributions is pretty tricky, but not hard. You first have to figure out what distributions you care about and then make all kinds of distribution specific file/configuration checks like in this example for the ones you've chosen, since you can't really support all of the myriad of Linux distros available out the. :-)
As for the Mac side i'll let the Mac experts answer, but it shouldn't be that hard, since at least the diversity issue is out of the question.

ncurses-like bindings in interpreted languages

Are there any bindings for ncurses or a similar menuing framework in interpreted languages that make the process of creating console menus and interacting with options absurdly simple?
I want to quickly prototype out a terminal-only configuration utility that runs on a Linux machine, in order to leverage some local resources previously installed.
There's a PERL module exposing CURSES:FORM and CURSES:WIDGETS, though I'm sure they're quite ancient. They may be fine for prototyping, however.
http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/tools.html#PERLCURSES
urwid for Python is pretty simple (see some examples) and is actively maintained.
The Dialog utility might be what you want.
The Python standard library comes with a curses module that you can use for this. Also, here is a HOWTO.

How to compile Intel Mac binaries on Linux?

I was reading an article about cross-compiling for OSX on linux, but it was quite hard to understand.
What tools do I need? And what configurations are necessary?
Are there any tools for creating packages too?
First you need odcctools, which contains assembler and linker and such (like binutils but capable of handling the Mach-O object format). Then you need the system libraries from the official SDK. You can download it from Apple, but must agree to some stuff and become a member to do so. And finally good old gcc. Quite easy in theory, but in reallity a horrible mess. The easiest way to go (that I know of) is to use I'm Cross!.
Update: I found a newer and better updated method called xchain. It requires more manual work than I'm Cross! thou.

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