HP Tru64 UNIX and TruCluster Server Version 5.1.B-4 Patch Summary and Release Notes (13156)

1.26.1 waitpid() System Call
Prior to the installation of this kit, the waitpid() system call failed to conform to the following
UNIX98 requirement:
A call to pid_t waitpid(pid_t pid, int *stat_loc, int options)
when
• the calling process has SA_NOCLDWAIT set or has SIGCHLD set to SIG_IGN
and
• has no unwaited for children that were transformed into zombie processes
shall block until all of its children terminate, fail, and set errno to ECHILD.
The new std_unix98 attribute enables waitpid( ) to conform to UNIX98 standard behavior.
For example, consider a situation in which a calling process has multiple children and no
unwaited-for child zombie and you call waitpid( ) with a specific child PID:
• If you set std_unix98=1 or std_unix98=4, waitpid( ) blocks until all of its children
terminate (UNIX98 standard behavior).
• If you set std_unix98=0 waitpid( ) blocks until any of its children exits.
1.26.2 poll() System Call
Prior to the installation of this kit, the poll() system call fails to conform to the following
UNIX98 requirement:
When no priority band has been written to on this STREAM, then a successful
call to int poll(struct pollfd fds[], nfds_t nfds, int timeout)
shall examine each element of the fds array for instances where the POLLWRBAND
flag is set in the events member and data for a priority band greater than 0 can
be written to the file descriptor specified by the fd member without blocking and
shall set the POLLWRBAND flag in the corresponding revents member when
found.
When no writes have taken place on any of the priority bands, a call to poll( ) blocks will time
out and return failure.
The poll( ) system call has been modified so if you need standards-compliant behavior, you
can use the new std_unix98 attribute.
If std_unix98 is set to a value of either 1 or 2, then the UNIX98_POLLWRBAND bit (defined as
a macro in the /usr/sys/include/sys/param.h file) gets set, which results in the internal
processing becoming indifferent to whichever external mapping of POLLWRBAND is in play. By
default, this bit in std_unix98 is not set, so poll( ) will behave the same way as it does today.
See the revised poll(2) reference page delivered in this kit.
1.27 New I/O Subsystem Attributes Can Improve Booting Speed
Three new I/O subsystem attributes control path registration during the boot process, allowing
systems with multiple paths to a large number of devices to boot faster. The following list provides
a brief description of these attributes. For additional information and settings, see the revised
sys_attrs_io(5) reference page delivered in this kit.
• boot_wait_hwc_reg
When disabled, causes a boot to the login prompt without waiting for hwc path registrations.
• hwc_reg_cmplt_notify_type
Controls how you get notified when device registration is done.
• hwc_registration_complete
Proves a query to determine if hwc path registration is complete.
26 Enhancements, Improvements, and Features