failing on windows?

[narimiran]

Based on Nim appveyor tests, this package fails on Windows.

I don't have Windows so I cannot reproduce, but I have been told that running nim c tests/teststream.nim produces ..\chronos\transports\stream.nim(287, 27) Error: 'writeStreamLoop' is not GC-safe as it performs an indirect call here/

This is likely connected to nim-lang/Nim@c86b1fb and could probably be fixed on your end by some extra {.gcsafe.} at some places.

[cheatfate]

Sorry but this is not Chronos bug, but new bug of Nim compiler. This function do not touch any global values which are in GC memory.

Until @Araq will not explain new gcsafe behavior properly in documentation or specification this issue will be closed.

[zah]

@cheatfate, the issue is that the code makes a call through a function pointer, which is not marked with gcsafe. The function pointer type is this one:

nim-chronos/chronos/asyncloop.nim

Line 243 in 9f15c6b

WSAPROC_TRANSMITFILE = proc(hSocket: SocketHandle, hFile: Handle,

Since the pointer is not gcsafe, in theory it's possible that a non-gcsafe function is assigned to it, so the compiler has to make the conservative assumption that the caller of the pointer (writeStreamLoop) may not be gcsafe as well.

[cheatfate]

@zah nim-lang/RFCs#142