“standards-based” libraries (all of the UNIX® implementations and VMS, which are moving to POSIX), the OS/2® library, and the Win32 library. (The NT and OS/2 libraries are fairly similar, which should not be too surprising. NT did start life as OS/2, version 2, after all.) Although the APIs1 and implementations differ significantly, the fundamental concepts are the same. The ideas in this book are valid for all three; the details of the APIs differ. All the specific discussion in this book focuses on the POSIX multithreading model, with comparisons to OS/2 and Win32 throughout.