Why it is necessary to compile the flatc executable file? - flatbuffers

Yesterday I compiled the necessary files to create the schemas but let me wondering why it was necessary to do all these steps to create the schemas, why those executables can't be shared directly as a release, is there something I'm missing?

We do provides a win32 executable for releases (https://github.com/google/flatbuffers/releases), and there are executables for Linux / OSX / Win for every commit and CI run here: https://github.com/google/flatbuffers/actions
Providing executables for Linux that will serve everyone is relatively difficult, with every distro having different versions of glibc and Linux somehow being static linking unfriendly, 32 vs 64 bit etc. So the CI executable may or may not work for you.
On Windows, a single statically linked win32 executable works for everyone, and Windows people are less used to compiling things themselves, hence why we provide it.

Related

Provide multiple toolchain options in CMake

I have an embedded project for ARM platform, specifically aarch64.
Up until now I was using Make. I recently set up CMake with no particular issues.
I moved to CMake because I was under the impression it was a more modern build tool that would have allowed a smarter configuration.
For example, I can compile my project using different toolchains (aarch64-elf-gcc-linaro, aarch64-linux-gnu-gcc,...) and I would like CMake to try if any of those are installed on the system and use whichever is found first by default.
Is this possible (or meant to)? I'd expect it to be an easy feat for the tool, but after searching for a while I can't seem to find the right track.
Yes, you can make your CMake project to search for available tool-chains installed in your OS, choose one and compile your project. I also write a CMake program for ARM embedded project, because now it is universal transferable between different OS system Windows and Unix. On Linux there is ARM ToolChain installed and on Windows there is Keil-MDK. If you have different tool-chains to choose between, you can write CMake script which will find paths with command like find_path() and then call correct "toolchianxx.cmake" script with right compiler flags for chosen compiler.
In your particular problem just use find_path commands and use hits to find installed compilers in "pre-set" known paths.

msys2 and mingw64 gcc version mismatch? (msys-perl)

I just installed msys2 and mingw64, with their development packages. I really need perl-Gtk3. Perl is msys2 and compiled with gcc-4.9.x, Gtk and friends are mingw and compiled with gcc-5.
Perl complains "Glib.c: loadable library and perl binaries are mismatched (got handshake key 0xde00080, needed 0xdd80080)" when building Glib. Should this work?
Thanks.
PS ... mingw-w64-x86_64-perl is simply unable to compile. And yes, I'm careful to use a mingw shell vs an msys shell.
Are you still having this problem? I have been able to build a Perl dev environment in MinGW64, current as of this time.
I have been able to build Perl Gtk2 / Gtk3 applications in that environment and the GUIs work. (Both Gtk2 and Gtk3 based). These applications are used in a production environment with several thousand desktop users. The application runs on OSX, Windows, and Linux, and can be packed into a binary for release as an "executable" for those operating systems. The details here are for the Windows version.
I do this by either installing the requisite system packages first with pacman, then as necessary rebuilding whatever system library packages that I may have modified, from source, using makepkg-mingw.
Then I build the requisite Perl modules using the CPAN shell, and the "look" command.
I use pkg-config to detect what library and header files are needed.
I then build (at minimum), the Perl Glib, Pango, Cairo, Gtk2, and Gtk3 modules using the perl Makefile.PL command.
The LIBS and INC options need to be added to that command to create a Makefile that includes the correct header files, and links to the correct libraries. The EXTRALIBS and LDLOADLIBS sections of the Makefile needs be correct.
Also ExtUtils::MM_Win32.pm ExtUtils::Liblist::Kid.pm needed to be edited due to the different archname reported by the MinGW64 perl.
I am only giving a general answer, because I was thinking offing a YouTube video on this. If this is a desired topic I will.

MXE compile on linux for linux

So I saw this project http://mxe.cc/ and tried it, it seems like it is very easy to compile stuff for windows with this. I tried to hack it a little bit to compile binaries for linux instead, because, if it compiles for other system so easily how can it be hard to compile for host? 90% of the stuff seems to just build out of the box, but there are some errors and therefore I cannot build. I want to ask, how correctly should I configure mxe to build for the linux host? I know this is not supported but I don't think it should be that hard because we build from source anyway. And there are next to no modifications for downloaded sources too (in a windows build that is).
For people who might ask why I don't want to use shared stuff, I want to basically have two options:
dpkg package for user with dependencies specified (the linux way)
single standalone static executable
Any suggestions? Or maybe there's whole another guide on linux on how to build things from scratch (without a lot of manual work like mxe does)?

Is there a way for cmake to automatically extend the system PATH variable to compiled executables?

Can cmake configuration files also be used to automatically extend the system PATH variable to include the directory paths to all the installed executable applications and if it is possible (and a standard practice), how can I do this?
This way, as soon as I configure all the CMakeLists.txt files and everything compiles (and hopefully runs) nicely, I can start using the applications, and the path configuration would be packaged together with the build process. I am working with Linux and my code is written in C++, but since cmake is cross-platform, the question extends to other systems as well.
I'm unaware of any capability in CMake to do this. However, we based what we do what Cantera does. They upgraded to SCONS recently instead of their old build system, but the idea still applies.
Anyway, there's a script that CMake configures with the paths during the configure step and then installs somewhere. So once built on Linux, one would run make install then source ~/setup_cantera and it sets up all the variables needed.
We do the same thing for our libraries built with CMake. It's possible to detect which shell the user is running and configure an appropriate template script.

run wxHaskell on other machine

I've compiled haskell program which uses wxHaskell library, now I would like to know how to make it run on other machines which doesn't have wxHaskell installed. Of course I can see errors and I can copy dlls written in output and copy them to that machine but what is professioal sollution, can I write any installer or something like that?
thanks for help
You will need to fully statically link your executable. How to do this varies from system to system, but in general involves passing the -static flag to GHC, and -optl-static to your linker.
If you use the recent cabalized wxHaskell implementations, it's pretty easy, since almost everything is statically linked.
I use InnoSetup, which is Open Source, and works very well. My script needs at least the following:
AppName=My Wonderful Application
AppVerName=My Wonderful Application 0.1.13
CreateAppDir=yes
DefaultDirName={pf}\MyWonderfulApplication
[Files]
Source: "path\to\your\wxWidgets.dll"
Source: "path\to\msvcrt.dll"
Source: "path\to\your\application.exe"
All of the paths except DefaultDirName are paths on your development machine.
The key items are your wxWidgets DLL (may be multiple DLLs, depending on how you built wxWidgets - I recommend and use the monolithic option, which creates a single DLL, wxmsw28u_gcc_custom.dll) and your application binary.
If you are linking to any other libraries, you will need them as well. Many 3rd party libraries on Windows require msvcrt.dll, which is why I've mentioned it.