Re: [Haskell-cafe] How to fix linker error on MacOS

from a recent rts/rts.cabal.in: -- Note [fd_set_overflow] -- ~~~~~~~~~~~~~~~~~~~~~~ -- In this note is the very sad tale of __darwin_fd_set_overflow. -- The 8.10.5 release was broken because it was built in an environment -- where the libraries were provided by XCode 12.*, these libraries introduced -- a reference to __darwin_fd_set_overflow via the FD_SET macro which is used in -- Select.c. Unfortunately, this symbol is not available with XCode 11.* which -- led to a linker error when trying to link anything. This is almost certainly -- a bug in XCode but we still have to work around it. -- Undefined symbols for architecture x86_64: -- "___darwin_check_fd_set_overflow", referenced from: -- _awaitEvent in libHSrts.a(Select.o) -- ld: symbol(s) not found for architecture x86_64 -- One way to fix this is to upgrade your version of xcode, but this would -- force the upgrade on users prematurely. Fortunately it also seems safe to pass -- the linker option "-Wl,-U,___darwin_check_fd_set_overflow" because the usage of -- the symbol is guarded by a guard to check if it's defined.

On 26 Jun 2021, at 6:47 pm, David Banas wrote:

How do I fix this (from `cabal build`)?

Undefined symbols for architecture x86_64: "___darwin_check_fd_set_overflow", referenced from: _awaitEvent in libHSrts.a(Select.o)

System Info: =========

$ ghc --version The Glorious Glasgow Haskell Compilation System, version 8.10.5

$ cabal --version cabal-install version 3.4.0.0 compiled using version 3.4.0.0 of the Cabal library

dbanas@Davids-MBP-2:~/Documents/Luminous/Projects/haskarch $ sw_vers ProductName: Mac OS X ProductVersion: 10.14.6 BuildVersion: 18G9216

-- Viktor.