HP 3000 Manuals

MPE/iX Developer's Kit Reference Manual Volume I

What Is the POSIX/iX Library? 

The POSIX/iX library is an implementation on 900 Series HP 3000 computer
systems of many of the C library functions and features defined in the
following:

   *   IEEE Standard 1003.1-1990 (ISO/IEC 9945-1:1990)
   *   Appendix B of the IEEE P1003.2/D11.2

MPE/iX 5.0 Documentation