blob: bfc6ee9fc86d6e7fc0be56dea6ed5251e7bd6386 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
|
{- BSD kqueue file modification notification interface
-
- Copyright 2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
{-# LANGUAGE ForeignFunctionInterface #-}
module Utility.Kqueue ( waitChange ) where
import Common
import System.Posix.Types
import Foreign.C.Types
import Foreign.C.Error
import Foreign.Ptr
import Foreign.Marshal
foreign import ccall unsafe "libkqueue.h waitchange" c_waitchange
:: Ptr Fd -> IO Fd
waitChange :: [Fd] -> IO (Maybe Fd)
waitChange fds = withArray fds $ \c_fds -> do
ret <- c_waitchange c_fds
ifM (safeErrno <$> getErrno)
( return $ Just ret
, return Nothing
)
where
safeErrno (Errno v) = v == 0
|