4 (3.2.5, IBM XL C Compiler)
8 (3.x, original Apple C Compiler oder GNU C)
11 <a href="http://www.freebsd.org/">FreeBSD</a>
15 <a href="http://www.hp.com/">HP-UX</a>
19 <a href="http://www.hp.com/">HP-UX</a>
24 (6.5, SGI MIPSpro C 7.30)
27 <a href="http://www.linux.org/">Linux</a>
28 (2.2.x/i386, 2.4.x/i386 und 2.4.x/hppa, GNU C)
31 <a href="http://www.apple.com/macosx/">Mac OS X</a>
32 (10.x, GNU C 2.95.x/3.x/4.01)
35 <a href="http://www.netbsd.org/">NetBSD</a>
36 (1.5.2/i386 und 1.5.3/m68k, GNU C)
39 <a href="http://www.obenbsd.org/">OpenBSD</a>
43 <a href="http://www.sun.com/">Solaris</a>
44 (2.5.1 und 2.6, GNU C)
47 Windows mit <a href="http://sources.redhat.com/cygwin/">Cygwin</a>