dist/build/System/Posix/DynamicLinker/ByteString.hs

{-# LINE 1 "System/Posix/DynamicLinker/ByteString.hsc" #-}

{-# LINE 2 "System/Posix/DynamicLinker/ByteString.hsc" #-}
{-# LANGUAGE Trustworthy #-}

{-# LINE 4 "System/Posix/DynamicLinker/ByteString.hsc" #-}
-----------------------------------------------------------------------------
-- |
-- Module : System.Posix.DynamicLinker.ByteString
-- Copyright : (c) Volker Stolz <vs@foldr.org> 2003
-- License : BSD-style (see the file libraries/base/LICENSE)
-- 
-- Maintainer : vs@foldr.org
-- Stability : provisional
-- Portability : non-portable (requires POSIX)
--
-- Dynamic linker support through dlopen()
-----------------------------------------------------------------------------

module System.Posix.DynamicLinker.ByteString (

 module System.Posix.DynamicLinker.Prim,
 dlopen,
 dlsym,
 dlerror,
 dlclose,
 withDL, withDL_,
 undl,
 )

-- Usage:
-- ******
-- 
-- Let's assume you want to open a local shared library \'foo\' (.\/libfoo.so)
-- offering a function
-- @char \* mogrify (char\*,int)@
-- and invoke @str = mogrify("test",1)@:
-- 
-- 
-- type Fun = CString -> Int -> IO CString
-- foreign import dynamic unsafe fun__ :: FunPtr Fun -> Fun
-- 
-- withDL "libfoo.so" [RTLD_NOW] \$ \\ mod -> do
-- funptr <- dlsym mod "mogrify"
-- let fun = fun__ funptr
-- withCString "test" \$ \\ str -> do
-- strptr <- fun str 1
-- strstr <- peekCString strptr
-- ...
-- 

where

import System.Posix.DynamicLinker.Common
import System.Posix.DynamicLinker.Prim


{-# LINE 55 "System/Posix/DynamicLinker/ByteString.hsc" #-}

import Control.Exception ( bracket )
import Control.Monad	( liftM )
import Foreign
import System.Posix.ByteString.FilePath

dlopen :: RawFilePath -> [RTLDFlags] -> IO DL
dlopen path flags = do
 withFilePath path $ \ p -> do
 liftM DLHandle $ throwDLErrorIf "dlopen" (== nullPtr) $ c_dlopen p (packRTLDFlags flags)

withDL :: RawFilePath -> [RTLDFlags] -> (DL -> IO a) -> IO a
withDL file flags f = bracket (dlopen file flags) (dlclose) f

withDL_ :: RawFilePath -> [RTLDFlags] -> (DL -> IO a) -> IO ()
withDL_ file flags f = withDL file flags f >> return ()