nim v1.2.0 with cygwin gcc: Compiling any code gives error: ‘_O_BINARY’ undeclared (first use in this function); did you mean ‘O_BINARY’?

[zhopan77]

Versions:
Nim Compiler Version 1.2.0 [Windows: amd64]
Compiled at 2020-04-03
Copyright (c) 2006-2020 by Andreas Rumpf

git hash: 7e83adf
active boot switches: -d:release

Windows 10 64-bit.

Any code, even a simple helloworld.nim wouldn't compile, regardless how I installed Nim (either through choosenim or direct download). The message is:

C:\GoogleDrive\Learning\NimLearning>nim c -r "c:\GoogleDrive\Learning\NimLearning\Oct2019\HelloWorld.nim"
Hint: used config file 'C:\nim-1.2.0\config\nim.cfg' [Conf]
Hint: system [Processing]
Hint: widestrs [Processing]
Hint: io [Processing]
Hint: HelloWorld [Processing]
c:\GoogleDrive\Learning\NimLearning\Oct2019\HelloWorld.nim(19, 6) Hint: 'yes' is declared but not used [XDeclaredButNotUsed]
CC: stdlib_io.nim
C:\Users\zpan\nimcache\HelloWorld_d\stdlib_io.nim.c: In function ‘stdlib_ioInit000’:
C:\Users\zpan\nimcache\HelloWorld_d\stdlib_io.nim.c:509:16: error: ‘_O_BINARY’ undeclared (first use in this function); did you mean ‘O_BINARY’?
  509 |  _setmode(T1_, _O_BINARY);
      |                ^~~~~~~~~
      |                O_BINARY
C:\Users\zpan\nimcache\HelloWorld_d\stdlib_io.nim.c:509:16: note: each undeclared identifier is reported only once for each function it appears in
Error: execution of an external compiler program 'gcc.exe -c  -w -mno-ms-bitfields   -IC:\nim-1.2.0\lib -Ic:\GoogleDrive\Learning\NimLearning\Oct2019 -o C:\Users\zpan\nimcache\HelloWorld_d\stdlib_io.nim.c.o C:\Users\zpan\nimcache\HelloWorld_d\stdlib_io.nim.c' failed with exit code: 1

I'm using gcc 9.3.0 from cygwin:

zpan@WSPWORK C:\Users\zpan
$ where gcc
C:\cygwin64\bin\gcc.exe

zpan@WSPWORK C:\Users\zpan
$ gcc --version
gcc (GCC) 9.3.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

[zhopan77]

OK I tried using scoop to install nim and use the gcc installed by scoop instead. Compiling worked.

zpan@WSPWORK C:\Users\zpan
$ where gcc
c:\Users\zpan\scoop\apps\gcc\8.1.0.0\bin\gcc.exe
C:\Users\zpan\scoop\apps\gcc\current\bin\gcc.exe

zpan@WSPWORK C:\Users\zpan
$ gcc --version
gcc (x86_64-posix-seh-rev0, Built by MinGW-W64 project) 8.1.0
Copyright (C) 2018 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

So I suspect this is due to gcc version. After downgrading to gcc 8.3.0 in cygwin, the compilation still does not work. So it seems cygwin's gcc just wouldn't work.

[alaviss]

This is pretty much expected. The code generated by the Nim compiler targets specifically Windows, not Cygwin.

Cygwin is a POSIX-emulated environment to allow POSIX-compatible code to compile and run natively on Windows. Nim doesn't target this environment, it targets win32 directly, which is why you'll need the mingw compiler to compile the code.

[Araq]

Cygwin is not supported.