The following strerror() call is problematic on some platforms: ``` foreign import ccall unsafe "string.h" strerror :: Errno -> IO (Ptr CChar) errnoToIOError :: String -- ^ the location where the error occurred -> Errno -- ^ the error number -> Maybe Handle -- ^ optional handle associated with the error -> Maybe String -- ^ optional filename associated with the error -> IOError errnoToIOError loc errno maybeHdl maybeName = unsafePerformIO $ do str <- strerror errno >>= peekCString return (IOError maybeHdl errType loc str (Just errno') maybeName) ``` ``` The strerror() function need not be thread-safe. ``` ``` On some systems, strerror() returns NULL if the error number is unknown. (...) C99 and POSIX.1-2008 require the return value to be non-NULL. ``` * https://man7.org/linux/man-pages/man3/strerror.3p.html * https://man7.org/linux/man-pages/man3/strerror.3.html Version: base-4.19.0.0 Module: Foreign.C.Error