Regression in Cygwin 3.2.0

Takashi Yano
Sat Apr 17 12:37:14 GMT 2021

On Fri, 16 Apr 2021 11:17:50 +0100
David Allsopp wrote:
> I'm unable to build OCaml using the mingw-w64 compilers with Cygwin 3.2.0.
> Windows 10.0.19042.928 (and tried on three different machines so far)
> Repro:
>  - Fresh Cygwin64 installation with make, libiconv, mingw64-x86_64-gcc-core
> and git added; fire up mintty
>  - git clone --depth 1 --recursive
>  - cd ocaml && ./configure --host=x86_64-w64-mingw32 && make -j8 flexdll &&
> make -j8 world.opt
> This is consistently hanging with Cygwin 3.2.0 and seems possibly to have
> something to do with linking (the creation of runtime/ocamlrun.exe and
> stdlib/camlheader, which is also an executable, seem to be part of the
> problem).
> It can be immediately fixed by downgrading to Cygwin 3.1.7, cleaning the
> tree and repeating the build.
> I'm of course very happy to try to reduce this to a smaller repro case, but
> is there an obvious culprit in Cygwin 3.2.0 to check before I do?

Thanks for the report. I looked into this problem and found
that the caused is the combination of some race issues for
non-cygwin processes in pty and console code.

I will submit the patches fixing this issue.

Takashi Yano <>

More information about the Cygwin mailing list