HP Tru64 UNIX and TruCluster Server Version 5.1B-5 Patch Summary and Release Notes (March 2009)

See the revised sys_attris_generic(5) reference page delivered in this kit for more
information. Refer to the standards(5) reference page for more information about industry
standards and associated tags.
3.2.1.26.1 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.
3.2.1.26.2 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
3.2 Prior Release Notes 53