Installation guide

G.8.9 POSIX 1003.1b Realtime Signals
Realtime signals have been implemented to conform to the POSIX 1003.1b
standard. This new feature includes queued signals with optional data
delivery, and 16 user-definable realtime signals.
The following functions to support realtime signals were implemented:
sigqueue
sigtimedwait
sigwaitinfo
timer_getoverrun
G.8.9.1 ULTRIX Migration Issues
There are no ULTRIX migration issues.
G.8.10 POSIX 1003.1b Synchronized I/O
Synchronized I/O (file synchronization) has been implemented to conform to
the POSIX 1003.1b standard. New functions for synchronized I/O under the
UFS and AdvFS file systems include:
aio_fsync
Asynchronously writes changes in a file to permanent storage
fdatasync
Writes data changes in a file to permanent storage
The open function now takes the following new flags for synchronized I/O:
O_DSYNC
Ensures synchronized I/O data integrity of the file accessed
O_RSYNC
Used for synchronized I/O read operations
G.8.10.1 ULTRIX Migration Issues
There are no ULTRIX migration issues.
G.8.11 POSIX 1003.1b _POSIX_C_SOURCE Symbol
For applications conforming to POSIX 1003.1b, the _POSIX_4SOURCE
macro is supported for DIGITAL UNIX Version 4.0B, but will be retired
with the next release of DIGITAL UNIX. The macro _POSIX_4SOURCE is
Migration from ULTRIX Version 4.5 to DIGITAL UNIX Version 4.0B G–15