id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
3214	"""undefined reference to..."" when compiling parallel code"	fhsanches		"First of all, sorry if it's not a bug in GHC, but I just don't know where to file it.

When compiling a file that imports Control.Parallel (par), I receive the following error:

death-star% ghc par.hs -O2
par.o: In function `s15L_info':
(.text+0xce3): undefined reference to `__stginit_parallelzm1zi0zi0zi0_ControlziParallel_'
collect2: ld returned 1 exit status

Disabling optimizations just make things worse:

death-star% ghc par.hs -fforce-recomp
par.o: In function `r6b_info':
(.text+0x106d): undefined reference to `parallelzm1zi0zi0zi0_ControlziParallel_par_closure'
par.o: In function `sEr_info':
(.text+0x143b): undefined reference to `__stginit_parallelzm1zi0zi0zi0_ControlziParallel_'
par.o: In function `r6b_srt':
(.data+0x368): undefined reference to `parallelzm1zi0zi0zi0_ControlziParallel_par_closure'
collect2: ld returned 1 exit status

Is this a bug in GHC? In ld? Any missing dependency in my distro?

I'm using Ubuntu 9.04, GHC 6.8.2 built from the repositories.

Thanks for your time.
"	bug	closed	normal		Compiler	6.8	invalid	undefined reference		Linux	Unknown/Multiple		Unknown