On Monday, 20 July 2020 at 22:05:35 UTC, WhatMeWorry wrote:
2) "The total size of a static array cannot exceed 16Mb" What limits this? And with modern systems of 16GB and 32GB, isn't 16Mb excessively small? (an aside: shouldn't that be 16MB in the reference instead of 16Mb? that is, Doesn't b = bits and B = bytes)
I didn't know this but it makes sense and I guess this is a constraint of the D language itself. In practice 16MB should be well enough for most cases. I'm not sure where 16MB is taken from, if there is any OS out there that has this limitation or if it was just taken as an adequate limit.
Let's say you have a program with 4 threads, then suddenly the TLS area is 4 * 16 MB = 64MB. This size rapidly increases with number of threads and TLS area size. Let's say TLS area of 128MB and 8 threads, which gives you a memory consumption of 1GB. That's how quickly it starts to consume memory if you don't limit the TLS variables.
If you want global variables like in good old C/C++, then use __gshared. Of course you have to take care if any multiple accesses from several threads.
