AIX 4.3.[23], 5L, and 5.1 Apple Darwin 1.[23] for Power Macintosh systems BSDI BSD/OS 4.1 for Intel-based systems DEC OSF/1, Digital UNIX, Tru64 UNIX 4.0, and 5.[01] FreeBSD 4.[23] and 5.0 for Intel-based systems HP-UX 11.00 and 11.11 Linux 2.1.72 and above for Intel-based systems NetBSD 1.5 for Alpha, Intel, and SPARC-based systems NEXTSTEP 3.[13] for NEXTSTEP architectures OpenBSD 2.[89] for Intel-based systems OpenStep 4.x SCO OpenServer Release 5.0.[45] for Intel-based systems SCO UnixWare 7.1.1 for Intel-based systems Sequent PTX 4.4[.46], 4.5[.1], and 4.6[.1] for Sequent systems Solaris 2.6, 7, 8, and 9 BETA