[arch-haskell] Codec-Image-DevIL, Arch Linux, haskell-codec-image-devil

[Gregory D. Weber]

I.  Problem: Codec-Image-DevIL 0.1 and 0.2.0 will not build on Arch Linux 

A.  Attempted installation from Arch User Repository (AUR)

I attempted to install the package 
haskell-codec-image-devil 0.2.0-2
(http://aur.archlinux.org/packages.php?ID=18919)
with bauerbill:

$ bauerbill --aur -Sy haskell-codec-image-devil
...
==> Starting build()...
Configuring Codec-Image-DevIL-0.2.0...
Setup: Missing dependency on a foreign library:
* Missing C library: IL
This problem can usually be solved by installing the system package that
provides this library (you may need the "-dev" version). If the library is
already installed but in a non-standard location then you can use the flags
--extra-include-dirs= and --extra-lib-dirs= to specify where it is.
==> ERROR: Build Failed.
    Aborting...
ERROR: makepkg exited with an error (512)
ERROR: no package found: /tmp/bauerbill/build/aur/haskell-codec-image-devil/haskell-codec-image-devil-0.2.0-2-x86_64.pkg.tar.gz
$

The error message "Missing C library: IL" is incorrect: 
the Arch 'devil' package
is installed, and the include and library files are present in
the normal locations:

$ pacman -Q devil
devil 1.7.8-6
$ ls /usr/include/IL
devil_cpp_wrapper.hpp  il.h  ilu.h  ilu_region.h  ilut.h
$ ls /usr/lib/*IL*
/usr/lib/libIL.a          /usr/lib/libILU.a          /usr/lib/libILUT.a
/usr/lib/libIL.so@        /usr/lib/libILU.so@        /usr/lib/libILUT.so@
/usr/lib/libIL.so.1@      /usr/lib/libILU.so.1@      /usr/lib/libILUT.so.1@
/usr/lib/libIL.so.1.1.0*  /usr/lib/libILU.so.1.1.0*  /usr/lib/libILUT.so.1.1.0*

B.  Attempted installation from Hackage

Trying to install either version 0.1 or 0.2.0 from Hackage
yields essentially the same result:

$ runghc Setup configure
Configuring Codec-Image-DevIL-0.2.0...
Setup: Missing dependency on a foreign library:
* Missing C library: IL
This problem can usually be solved by installing the system package that
provides this library (you may need the "-dev" version). If the library is
already installed but in a non-standard location then you can use the flags
--extra-include-dirs= and --extra-lib-dirs= to specify where it is.
$

C.  Missing comment on AUR package page

Incidentally -- I'm pretty sure I posted a comment reporting 
the problem earlier this month (March 2010) on
http://aur.archlinux.org/packages.php?ID=18919

-- but the comment seems to have disappeared.
Or maybe I'm not going through the right hoops to view
comments -- I remember having that trouble before,
but can't remember the solution.

II.  Solution

There seem to be two errors, one involving Codec-Image-DevIL
and one involving Cabal.  I have solutions for the first,
but not the second.

A.  Fixing Codec-Image-DevIL

1.  Quick fix:

Edit Codec-Image-DevIL.cabal and replace the line

     Extra-Libraries: IL

with one of the following (take your choice):

     Extra-Libraries: IL, pthread
     Extra-Libraries: IL, rt
     Extra-Libraries: IL, pthread, rt

These all work in Arch Linux, and they also work (though they are not
needed) in Fedora 10.

2.  How I discovered this:

I wrote a small C program that calls a few DevIL functions
(such as ilInit, ilLoadImage) just to demonstrate that they are
truly there.

Compiling and linking with -lIL failed:

$ gcc -o ctestil -lIL ctestil.o 
/usr/lib/libIlmThread.so.6: undefined reference to `sem_init'
/usr/lib/libIlmThread.so.6: undefined reference to `sem_destroy'
/usr/lib/libIlmThread.so.6: undefined reference to `pthread_create'
/usr/lib/libIlmThread.so.6: undefined reference to `sem_post'
/usr/lib/libIlmThread.so.6: undefined reference to `sem_trywait'
/usr/lib/libIlmThread.so.6: undefined reference to `sem_getvalue'
/usr/lib/libIlmThread.so.6: undefined reference to `sem_wait'
/usr/lib/libIlmThread.so.6: undefined reference to `pthread_join'
collect2: ld returned 1 exit status

Reading 'man sem_init', I found the statement
"Link with -lrt or -pthread."  Sure enough, both of these
worked:
$ gcc -o ctestil -lIL -lrt ctestil.o 
$ gcc -o ctestil -lIL -pthread ctestil.o 

B.  Whether to fix Cabal?

But why is Cabal spuriously reporting the absence of libIL?
It is an error, isn't it?

I have the impression, formed from browsing around on
http://hackage.haskell.org/trac/hackage/, that in the
configuration step, when Cabal sees the line

Extra-Libraries: IL

it writes a small C program that tries to include that library,
and reports the library is missing if there's an error
in compiling it.  Maybe Cabal needs to interpret the
C compiler's error messages more carefully.

Greg


-- 
   ___   ___  __     _      
  / _ \ / _ \| |    | |     Gregory D. Weber, Associate Professor
 / /_\// / | | | /\ | |     Indiana University East
/ /_\\/ /__| | |/  \| |     http://mypage.iu.edu/~gdweber/
\____/\_____/\___/\__/      Tel. (765) 973-8420; FAX (765) 973-8550