Many needed header files and parts of the runtime implementation for the POSIX System Interface compatibility are missing or incomplete.


POSIX requires `_POSIX_VERSION` to be defined in `unistd.h` and Open Watcom uses:
```
#define _POSIX_VERSION   199809L
```

Expect features of newer POSIX System Interface versions to be missing.


There is no exact overview, which features of the advertised POSIX version are implemented and which features are still missing.


### POSIX Reference Documentation (The Open Group Base Specifications)

The standard can be viewed online: [The Open Group Base Specifications Issue 8/POSIX.1-2024](https://pubs.opengroup.org/onlinepubs/9799919799/)

An overview about the changes included in the `Open Group Base Specification Issue 8`: 
[Changes from Issue 7 to Issue 8](https://pubs.opengroup.org/onlinepubs/9799919799/xrat/V4_xsh_chap01.html)

***
## Open Watcom POSIX Compliance

| POSIX Version | Feature | Status | Notes |
| ------- | ----------------------------------------------- | ----- | ------------------------------------ |
| ??? | IP V6 | - | AF_INET6 is defined, but not implemented |


`-` means not yet implemented

`???` means unclear

***

