id,summary,reporter,owner,description,type,status,priority,milestone,component,version,resolution,keywords,cc,os,architecture,failure,difficulty,testcase,blockedby,blocking,related
4523,unix package does not check properly for sem_close,bos,igloo,"On modern Linux systems (in my case, Fedora 13 and 14), the {{{sem_close}}} and other functions are in the {{{rt}}} and {{{pthread}}} libraries.  This combination is not checked for properly by the {{{unix}}} package's {{{autoconf}}} script. As a result attempting to build the {{{unix}}} package will succeed, but linking applications against the misconfigured {{{unix}}} will result in undefined symbol errors for e.g. {{{sem_close}}}.

I believe that the C compiler needs to be invoked with {{{-pthread}}} for the right thing to happen, as {{{unix.buildinfo}}} contains a reference to {{{rt}}} that is nevertheless not enough:

{{{

buildable: True
cc-options: 
ld-options: 
extra-libraries:  rt util dl 
}}}

Here's my current workaround hack:

{{{

--- old-unix/configure.ac	2010-11-23 15:25:33.741849630 -0800
+++ new-unix/configure.ac	2010-11-23 15:25:33.760849987 -0800
@@ -215,6 +215,9 @@
 	PTHREAD_CFLAGS=-pthread
 	PTHREAD_LDFLAGS=-pthread
 	;;
+linux*)
+	PTHREAD_LIBS=pthread
+	;;
 esac
 AC_SUBST(PTHREAD_CFLAGS)
 AC_SUBST(PTHREAD_LDFLAGS)
}}}",bug,closed,high,7.0.2,libraries/unix,7.0.1,fixed,,,Linux,Unknown/Multiple,Building GHC failed,,,,,