fixed a size_t / uint64_t problem for macOS 10.12 and Clang 8.1.0

Created by: JasonRuonanWang

Created by: JasonRuonanWang

@chuckatkins I can change vector<size_t> to adios2::Dims if needed. But there has to be two sets of these variables, because some of the later code requires uint64_t, while some requires size_t. And this is ultimately because ADIOS 1 requires uint64_t and ADIOS 2 requires size_t. Thus it is unfixable without a substantial amount of work.

Created by: chuckatkins

I think @williamfgc was also suggesting that by fixing the printData signature you no longer need the separate set of arrays and can just declare readsize and offset as adios2::Dims variables and only use those.

Created by: JasonRuonanWang

@chuckatkins I totally understand. But if I do so, then I am essentially moving the problem from heatRead_adios2 to heatRead_adios1. Because, firstly, heatRead_adios1 is based on ADIOS 1 API which requires uint64_t, and secondly, it uses the printData function, which is now changed to size_t. So whichever type I use, I have to keep two sets of these variables in either heatRead_adios1 or heatRead_adios2.

Created by: chuckatkins

Ok, I understand the issue now in trying to marry the code base to work with adios1 and adios2 APIs. I didn't quite see that as I was only looking at it in isolation.

Created by: williamfgc

@JasonRuonanWang See my comment about making PrintData < T > a template function

Created by: JasonRuonanWang

@williamfgc Yeah, I kind of know this. I am just trying to avoid making too many changes. Because this is not my code, if I make too much modification then it might break something else while fixing the problem I have now. Do you want me to cancel this pull request? I can use Linux temporarily until someone fixes it.

Created by: williamfgc

I don't think @pnorbert would mind if @JasonRuonanWang changes PrintData to PrintData < T > to support uin64_t* and size_t* at the same time as that will solve an issue on Mac that we don't see on Linux. We are not changing the original logic.

Created by: JasonRuonanWang

@williamfgc Then I need to move the printData function from .cpp to .h, or create another .tcc file. In the meantime, there is only one function in the .cpp file, so if I do so, I probable need to remove the .cpp file then. You see, there is a lot of things... which I am not sure any of you would mind.

Created by: williamfgc

@JasonRuonanWang Then overload the function with size_t until @pnorbert checks the template solution, it's a copy and paste thing. Replacing is affecting adios1 example.

Created by: JasonRuonanWang

@williamfgc Done.

Created by: williamfgc

Thanks @JasonRuonanWang !