Issue #22400 has been updated by hsbt (Hiroshi SHIBATA). Status changed from Open to Closed Step 2 is merged in https://github.com/ruby/ruby/pull/19312, so String, Array and MatchData can now be 2GiB or longer on mswin. Next I'll work toward a 64-bit Fixnum on mswin (#14378) step by step, targeting Ruby 4.2. ---------------------------------------- Feature #22400: Use rb_long_t for lengths so that String and Array can exceed 2GiB on mswin https://bugs.ruby-lang.org/issues/22400#change-119576 * Author: hsbt (Hiroshi SHIBATA) * Status: Closed ---------------------------------------- On x64-mswin64, `long` is 32 bits while pointers are 64 bits. String, Array and MatchData keep their lengths in `long`, so none of them can reach 2GiB. ```ruby "a" * 2**31 # RangeError: bignum too big to convert into 'long' File.open(path, "rb") { it.read(2**31) } # RangeError Array.new(2**31) # RangeError ``` I propose giving these lengths and indices a type of their own, `rb_long_t`, in two steps. The first step is https://github.com/ruby/ruby/pull/18862. It defines `typedef long rb_long_t` everywhere and uses it for the lengths and indices of RString, RArray and RMatch, the C API that carries them, and the core, adding `LONGT2NUM`, `NUM2LONGT` and `PRIdLONGT`. A static assert keeps it `long`, so nothing changes, and `NUM2LONG` and `FIX2LONG` still return `long`. The second step makes `rb_long_t` 64 bits on mswin, as `rb_off_t` already does for `off_t` there. mingw keeps `long`, and Fixnum (#14378) stays as is. This breaks extensions that pass a `long *` to an out-parameter such as `rb_range_beg_len`, because Ruby then writes 8 bytes into a 4-byte variable. `-we4133` makes that a compile error, and I will send fixes to the gems it hits: nokogiri, google-protobuf, nokolexbor, string_view, readline-ext and iconv. An extension supporting older Ruby can `typedef long rb_long_t` when `RB_LONGT_MAX` is undefined. No existing type fits. `ssize_t` and `intptr_t` are `int` on ILP32 and would change `long *` parameters there. `SIGNED_VALUE` is already 64 bits on mswin, so it could not land as a no-op first. To catch new code that adds a plain `long` for a length, I would like a CI job that builds with `rb_long_t` set to `long long` on Linux, where `%ld` and `long *` mismatches fail. First, do you agree with this direction and with carrying it out? If so, is `rb_long_t` a good name? And since few C extensions are distributed for mswin, I think we could make the second step in 4.1 as well, without a transition period. What do you think? -- https://bugs.ruby-lang.org/