Issue #20524 has been reported by MSP-Greg (Greg L). ---------------------------------------- Misc #20524: mswin and gmp https://bugs.ruby-lang.org/issues/20524 * Author: MSP-Greg (Greg L) * Status: Open ---------------------------------------- Currently, the `vcpkg.json` file exists, and it can be used to specify what MSFT/vcpkg packages to install, and also a repo commit, which will determine the what package versions are used. The file lists the gmp package. 1. To use the gmp package in mswin, `win32/configure.bat` shows an option of `--with-gmp`. This option is not used in the `windows.yml` workflow file, nor is it mentioned in `doc/windows.md`. 2. When using the option, the build fails when compiling `bignum.c`, as it can’t find `gmp.h`. It appears the vcpkg include folder is not being passed to `cl`? So, it seems a few things are amiss. `gmp` was added a long time ago. With current mswin builds, will `gmp` improve `Bignum`’s performance? Is that unknown? If there are benchmarks to determine this, I could certainly run them… -- https://bugs.ruby-lang.org/