problems with ghc ffi

Simon Peyton-Jones simonpj@microsoft.com
Mon, 4 Nov 2002 14:41:09 -0000


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GHC questions to ghc-users please, not the main Haskell list.

=20

You need the -ffi flag to use the FFI.


S

=20

-----Original Message-----
From: David Abbs [mailto:u0da2@dcs.shef.ac.uk]=20
Sent: 04 November 2002 14:38
To: haskell@haskell.org
Subject: problems with ghc ffi

=20

I am having problems with the GHC FFI, I am using GHC version 5.04.1 and
am trying to compile the sample code given on=20
the web site
_______________________________________
module Foo where
=20
foreign export ccall foo :: Int -> IO Int
=20
foo :: Int -> IO Int
foo n =3D return (length (f n))
=20
f :: Int -> [Int]
f 0 =3D []
f n =3D n:(f (n-1))
_____________________________________
when I enter
c:/ghc M.hs=20
to compile the code I get the following error
M.hs:5: Type signature given for an expression
I have tried compiling the code using GHC 5.04.1 on windows 98, XP and
on Linux any help on would be=20
greatly appreciated.
_____________________________________________


David Abbs 3rd year Undergraduate in Computer Science=20


at the University Of Sheffield


_____________________________________________


u0da2@dcs.shef.ac.uk
Have a very nice day !!
=20

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<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>GHC questions to ghc-users please, =
not the
main Haskell list.</span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>&nbsp;</span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>You need the -ffi flag to use the =
FFI.</span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'><br>
S</span></font></p>

<p class=3DMsoNormal><font size=3D2 color=3Dnavy face=3DArial><span =
style=3D'font-size:
10.0pt;font-family:Arial;color:navy'>&nbsp;</span></font></p>

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0cm 4.0pt'>

<p class=3DMsoNormal><font size=3D2 face=3DTahoma><span lang=3DEN-US =
style=3D'font-size:
10.0pt;font-family:Tahoma'>-----Original Message-----<br>
<b><span style=3D'font-weight:bold'>From:</span></b> David Abbs
[mailto:u0da2@dcs.shef.ac.uk] <br>
<b><span style=3D'font-weight:bold'>Sent:</span></b> 04 November 2002 =
14:38<br>
<b><span style=3D'font-weight:bold'>To:</span></b> =
haskell@haskell.org<br>
<b><span style=3D'font-weight:bold'>Subject:</span></b> problems with =
ghc ffi</span></font></p>

<p class=3DMsoNormal><font size=3D3 face=3D"Times New Roman"><span =
style=3D'font-size:
12.0pt'>&nbsp;</span></font></p>

<div><pre><font size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:
Arial'>I am having problems with the GHC FFI, I am using GHC version =
5.04.1 and am trying to compile the sample code given on =
</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>the web =
site</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>____________________________=
___________</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>module Foo =
where</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>&nbsp;</span></font></pre><p=
re><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>foreign export ccall foo :: =
Int -&gt; IO Int</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>&nbsp;</span></font></pre><p=
re><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>foo :: Int -&gt; IO =
Int</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>foo n =3D return (length (f =
n))</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>&nbsp;</span></font></pre><p=
re><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>f :: Int -&gt; =
[Int]</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>f 0 =3D =
[]</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>f n =3D n:(f =
(n-1))</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>____________________________=
_________</span></font></pre><pre><font
size=3D2 face=3D"Courier New"><span style=3D'font-size:10.0pt'>when I =
enter</span></font></pre><pre><font
size=3D2 face=3D"Courier New"><span style=3D'font-size:10.0pt'>c:/ghc =
M.hs </span></font></pre><pre><font
size=3D2 face=3D"Courier New"><span style=3D'font-size:10.0pt'>to =
compile the code I get the following error</span></font></pre><pre><font
size=3D2 face=3D"Courier New"><span style=3D'font-size:10.0pt'>M.hs:5: =
Type signature given for an expression</span></font></pre><pre><font
size=3D2 face=3D"Courier New"><span style=3D'font-size:10.0pt'>I have =
tried compiling the code using GHC </span></font><font
face=3DArial><span style=3D'font-family:Arial'>5.04.1 on windows 98, XP =
and on Linux any help on would be </span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>greatly =
appreciated.</span></font></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>____________________________=
_________________<br>
David Abbs 3rd year Undergraduate in Computer Science <br>
at the University Of Sheffield<br>
_____________________________________________<br>
<a =
href=3D"mailto:u0da2@dcs.shef.ac.uk">u0da2@dcs.shef.ac.uk</a></span></fon=
t></pre><pre><font
size=3D2 face=3DArial><span =
style=3D'font-size:10.0pt;font-family:Arial'>Have a very nice day =
!!</span></font></pre><pre><font
size=3D2 face=3D"Courier New"><span =
style=3D'font-size:10.0pt'>&nbsp;</span></font></pre></div>

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