AIX Version 4.3 Differences Guide

%y is now defined such that, when a century is not otherwise specified, values in
the range 69-99 refer to the twentieth century, and values in the range 00-68 refer
to the twenty-first century.
4.2.4.3 date Command
Century handling has been added as follows:
# date mmddhhmm[[cc]yy]
cc is the century specifier.
4.2.4.4 prs Command
The prs command is part of SCCS and has been changed such that the -c option
-c cutoff
indicates the cut off date-time, in the form:
YY[MM[DD[HH[MM[SS]]]]]
The YY specifier is a two digit specifier to the year and, therefore, does not
denote the century. YY is now defined such that values in the range 69-99 refer to
the twentieth century, and values in the range 00-68 refer to the twenty-first
century.
4.3 M:N Pthreads (4.3.1)
AIX 4.3.1 replaced the previous 1:1 threads implementation model with an M:N
version. The M:N model complies with the UNIX98 pthreads standard, which
includes the POSIX pthreads standard. Previous releases of AIX Version 4
complied with Draft 7 of the POSIX pthreads standard. AIX 4.3.1 is binary
compatible with previous releases. The UNIX98 implementation is the default for
application development, but you can use the cc_r7 or xlc_r7 compiler interfaces
to develop new applications using Draft 7 pthreads. Users may need to alter
existing source code to obtain the required function on AIX 4.3.1 using the default
UNIX98 pthreads library.
4.3.1 Porting Application from Draft 7 Pthreads
There are very few differences between Draft 7 and the final standard.
• There are some minor errno differences. The most prevalent is the use of
ESRCH to denote the specified pthread could not be found. Draft 7 frequently
returns EINVAL for this failure.
• Pthreads are joinable by default. This is a significant change since it can result
in a memory leak if ignored.
• Pthreads have process scheduling scope by default.
• The subroutine pthread_yield has been replaced by sched_yield.
• The various scheduling policies associated with the mutex locks are slightly
different.
Application Development and Pthreads 71