{-# LANGUAGE CPP #-}
{-# LANGUAGE Safe #-}

module Data.Time.Clock.Internal.CTimeval where

#ifndef mingw32_HOST_OS
-- All Unix-specific, this
import Foreign
import Foreign.C

data CTimeval =
    MkCTimeval CLong
               CLong

instance Storable CTimeval where
    sizeOf _ = (sizeOf (undefined :: CLong)) * 2
    alignment _ = alignment (undefined :: CLong)
    peek p = do
        s <- peekElemOff (castPtr p) 0
        mus <- peekElemOff (castPtr p) 1
        return (MkCTimeval s mus)
    poke p (MkCTimeval s mus) = do
        pokeElemOff (castPtr p) 0 s
        pokeElemOff (castPtr p) 1 mus

foreign import ccall unsafe "time.h gettimeofday" gettimeofday :: Ptr CTimeval -> Ptr () -> IO CInt

-- | Get the current POSIX time from the system clock.
getCTimeval :: IO CTimeval
getCTimeval =
    with
        (MkCTimeval 0 0)
        (\ptval -> do
             throwErrnoIfMinus1_ "gettimeofday" $ gettimeofday ptval nullPtr
             peek ptval)
#endif
