Hi, Jason.
Thank you for your explanations. They were very useful. In the light of what you said, I modified the programs as shown below (commented lines failed to work). Forcing the C function to return a number, wrapping the returned number in IO, and printing the number, I succeeded in bringing falures down to 1 case in 20 trials (average). By the way, I talked to doctors who work with capnograms, and they said that all Windows or Linux machines have problems in closing communication ports. However, it seems that capnographs are not turned off very often. I mean, when the doctor move the capnograph from one patient to another, s/he turns off the instrument. Therefore, this behavior does not create problems. However, what bothers me is that Clean always succeds in closeing the port.
{-# LANGUAGE ForeignFunctionInterface #-}
{- file: SER/IAL.hs -}
module SER.IAL where
import Control.Monad
import Foreign
import Foreign.C.Types
import Foreign.C
foreign import ccall "rs232.h opencport" opencport :: CInt -> IO ()
-- foreign import ccall "rs232.h closecport" closecport :: CInt -> CInt
-- foreign import stdcall unsafe "rs232.h closecport" closecport :: IO ()
-- foreign import ccall unsafe "rs232.h closecport" c_closecport :: CInt
foreign import ccall unsafe "rs232.h closecport" c_closecport :: CInt -> CInt
closecport :: Int -> IO Int
closecport n= return (fromIntegral (c_closecport (fromIntegral n)))
foreign import ccall "rs232.h rdrs232" c_sendmsg :: CInt -> CString -> CString
sendMessage :: Int -> String -> IO String
sendMessage n msg =
withCString msg $
\str -> peekCString (c_sendmsg (fromIntegral n) str)
{- file: sensors.hs -}
import Gui.Binding
import Gui.Types
import Gui.Constants
import SER.IAL
import Control.Monad
import Data.Char
main = do rv <- j_start
frame <- j_frame "Sensors"
avg <- j_button frame "Sampling"
j_setpos avg 20 150
j_setsize avg 90 30
rb <- j_button frame "Read"
j_setpos rb 125 150
j_setsize rb 90 30
tb <- j_button frame "Acquisition"
j_setpos tb 230 150
j_setsize tb 90 30
fld <- j_textfield frame 40
j_setpos fld 20 100
menubar <- j_menubar frame
file <- j_menu menubar "File"
quitMI <- j_menuitem file "Quit"
j_show frame
opencport(3)
waitForFrameAction frame fld rb tb avg quitMI
r <- closecport 5
putStrLn (show r)
return j_quit
waitForFrameAction frame f rb tb avg q =
do obj <- j_nextaction
again <- if obj == event q then return False
else if obj == event rb then
(do msg <- sendMessage 1 "r"
putStrLn msg
return True)
else if obj == event tb then
(do
tx <- sendMessage 1 "t"
let tp= filter (> ' ') tx
j_settext f tp
return True)
else if obj == event avg then
(do ok <- sendMessage 1 "m"
val <- j_gettext f 300
ns <- sendMessage 2 val
putStrLn ((filter (> ' ') ok) ++ ns)
return True)
else
(do
tx <- sendMessage 1 "t"
let tp= filter (> ' ') tx
rx <- sendMessage 1 "x"
let rd= filter (> ' ') rx
let x = hex2dec rd
let tt= (fromIntegral x)*209.1/1023.0 - 67.23
j_settext f ((show tt)++" ==> "++tp)
return True)
if not again
then return True
else waitForFrameAction frame f rb tb avg q
hex2dec :: String -> Int
hex2dec h= sum (zipWith (*)
(map (16^) [3,2,1,0])
[digitToInt c | c <- h])
convert d r s0= (fromIntegral (hex2dec d))*r/1024.0- s0
{- 1a43 67.23; 082b - 209.1 -}
// file: serial.c
#include "serial.h"
#include
I don't know how to mark the call unsafe. [...] I am running the main program on Windows.
Marking it unsafe is done by putting "unsafe" in the foreign import declaration. Even if it turns out not to fix the problem, it reduces the overhead of foreign calls (and is safe as long as they aren't going to call back into Haskell). Because your on Windows, you want to use "stdcall", as mentioned by Daniel Fischer. Thus the full declaration is: foreign import stdcall unsafe "rs232.h closecport" closecport :: IO () Let us know if this helps.
Here is the compilation script:
ghc -fglasgow-exts serial.c %1.hs -L./ -ljapi --make erase *.hi erase *.o strip %1.exe
I encourage you to look into Cabal soon :) -- Jason Dusek __________________________________________________________________ Make your browsing faster, safer, and easier with the new Internet Explorer® 8. Optimized for Yahoo! Get it Now for Free! at http://downloads.yahoo.com/ca/internetexplorer/