Hi, some oddities let the user001 test of the unix package fail on getGroupEntryFor*. One reason is that sysconf(_SC_GETGR_R_SIZE_MAX) returns 1024 on OpenBSD, while getgr*_r(3) actually need a buffer of 1024 + 200 * sizeof(char*) bytes. Note that the grBufSize = 2048 workaround in User.hsc did not work on 64 bit machines with OpenBSD, even before the _SC_GETGR_R_SIZE_MAX sysconf had been introduced. Instead of fiddling with stupid numbers again, I just implemented the try / enlarge / try harder scheme mentioned for example at http://www.opengroup.org/onlinepubs/9699919799/functions/getgrgid.html And I did so for all four functions, just in case there are existing problems with other unices (OpenBSD only needs the getGroupEntryFor* fixes). My Haskell sucks badly, so if someone has a cleaner solution: feel free use it instead of my patch ;-) Ciao, Kili