I just started collaborating remotely on a project. Project manager explicitly asked me to download Dart SDK 32bit version. Since I have 64bit machine I asked why to find out more about it. I was told that "we're compiling the Dart code into Javascript that will then run within website/webapp. Therefore," he said " we need to avoid compatibility issues with 32bit machines visiting our site."

I've been programming javascript for 8 years. I never came across any web javascript API that would come near problems such as 32/64bit. So what am I missing? How can SDK bit version affect produced .js code? I decided to ask here before I raise any argument, especially since it's not really important whether I use 32/64 bit in this case.

  • In practice, 64 bit is only going to matter if your SDK needs to address more than 4GB of memory directly, which seems unlikely. Aug 23, 2015 at 0:32
  • I had the impression that in languages where 32/64bit matters, performance is optimal when using 64bit on 64bit system. Aug 25, 2015 at 15:14
  • The only way to know for sure is to measure. Aug 25, 2015 at 16:30

1 Answer 1


I would have to agree with you that generating javascript ought to be the same whether from the 32-bit or 64-bit SDK. Further, I fail to see the project manager's concern about 32-bit clients visiting your site.

However, it is conceivable that despite all intentions to the contrary, the 32-bit and 64-bit software (SDK) behave differently (i.e. one has a bug that the other one doesn't have).

I am a big fan of having a well-known and documented baseline of tools for a project, of having reproducible results across development machines. In fact, in some organizations I've been part of compare the output of development (e.g. binaries) to make sure that the software being released is the same as that being (source) archived and is the same as what was actually tested. I've seen more than a few bugs caught by being that methodical (mostly bugs in the build system where clean didn't fully clean, so old binary stuff was unknowingly being used instead of recompiled).

So, in general, I'd be in favor of settling on which SDK to use in advance, and everyone using the identical SDK.

  • Thanks for the additional note explaining why it's better to stick to same distribution. I agree with that. Aug 22, 2015 at 21:48

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