POSIX.5 is an IEEE (IEEE Standard 1003.5b-1996) and ISO (ISO/IEC 14519:2001) standard defining an Ada interface to the POSIX system calls. The scope for the standard is the same as in POSIX.1 (C API) but defines a thick binding for the interface, thus benefiting from Ada features. Some functionality provided by POSIX.1, but already present in Ada, is skipped.
There exists an open-source implementation for GNAT called Florist (Florida State University/Forest), originally written by the Florida State University and eventually maintained by AdaCore.
The following compilers are known to provide an implementation of the standard: ObjectAda for Linux , GNAT , MAXAda  and PowerAda . There is an implementation for GNAT over Windows called wPOSIX (formerly Win32POSIX).
- Formerly Florida State University, now Adacore
- Project Info
- SVN Archive
- Pascal Obry and AdaCore.
- POSIX in Ada — Appendix to “Understanding Unix/Linux Programming”. Includes complete examples.
ISO Working Group
- The ISO standard was considered for revision in 2006 . A list of POSIX functions (including XSI functions, also known as SysV IPC) not currently supported by the Ada standard was identified as possible expansion .
- In 2013, the working group states that the update effort has been cancelled  due to low adoption.