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#!/bin/sh
# This is a shell archive (produced by GNU sharutils 4.2).
# To extract the files from this archive, save it to some FILE, remove
# everything before the `!/bin/sh' line above, then type `sh FILE'.
#
# Made on 1998-11-10 14:42 EST by <jcej@caldera.lads.com>.
# Source directory was `/scsiA/home/jcej/projects/ACE_wrappers/docs/tutorials/017'.
#
# Existing files will *not* be overwritten unless `-c' is specified.
#
# This shar contains:
# length mode name
# ------ ---------- ------------------------------------------
# 422 -rw-rw-r-- hdr
# 44 -rw-rw-r-- bodies
# 843 -rw-rw-r-- page01.pre
# 419 -rw-rw-r-- page02.pre
# 739 -rw-rw-r-- page03.pre
# 478 -rw-rw-r-- page04.pre
# 375 -rw-rw-r-- page05.pre
#
save_IFS="${IFS}"
IFS="${IFS}:"
gettext_dir=FAILED
locale_dir=FAILED
first_param="$1"
for dir in $PATH
do
if test "$gettext_dir" = FAILED && test -f $dir/gettext \
&& ($dir/gettext --version >/dev/null 2>&1)
then
set `$dir/gettext --version 2>&1`
if test "$3" = GNU
then
gettext_dir=$dir
fi
fi
if test "$locale_dir" = FAILED && test -f $dir/shar \
&& ($dir/shar --print-text-domain-dir >/dev/null 2>&1)
then
locale_dir=`$dir/shar --print-text-domain-dir`
fi
done
IFS="$save_IFS"
if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED
then
echo=echo
else
TEXTDOMAINDIR=$locale_dir
export TEXTDOMAINDIR
TEXTDOMAIN=sharutils
export TEXTDOMAIN
echo="$gettext_dir/gettext -s"
fi
touch -am 1231235999 $$.touch >/dev/null 2>&1
if test ! -f 1231235999 && test -f $$.touch; then
shar_touch=touch
else
shar_touch=:
echo
$echo 'WARNING: not restoring timestamps. Consider getting and'
$echo "installing GNU \`touch', distributed in GNU File Utilities..."
echo
fi
rm -f 1231235999 $$.touch
#
if mkdir _sh01874; then
$echo 'x -' 'creating lock directory'
else
$echo 'failed to create lock directory'
exit 1
fi
# ============= hdr ==============
if test -f 'hdr' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'hdr' '(file already exists)'
else
$echo 'x -' extracting 'hdr' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'hdr' &&
<HTML>
<HEAD>
X <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
X <META NAME="Author" CONTENT="James CE Johnson">
X <TITLE>ACE Tutorial 017</TITLE>
</HEAD>
<BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F">
X
<CENTER><B><FONT SIZE=+2>ACE Tutorial 017</FONT></B></CENTER>
X
<CENTER><B><FONT SIZE=+2>Using the ACE_Barrier synch object</FONT></B></CENTER>
X
<P>
<HR WIDTH="100%">
SHAR_EOF
$shar_touch -am 1110144198 'hdr' &&
chmod 0664 'hdr' ||
$echo 'restore of' 'hdr' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'hdr:' 'MD5 check failed'
9991b747f6aff75784cbeb88a79c06fc hdr
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'hdr'`"
test 422 -eq "$shar_count" ||
$echo 'hdr:' 'original size' '422,' 'current size' "$shar_count!"
fi
fi
# ============= bodies ==============
if test -f 'bodies' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'bodies' '(file already exists)'
else
$echo 'x -' extracting 'bodies' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'bodies' &&
PAGE=2
barrier.cpp
Barrier_i.h
Barrier_i.cpp
SHAR_EOF
$shar_touch -am 1110144198 'bodies' &&
chmod 0664 'bodies' ||
$echo 'restore of' 'bodies' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'bodies:' 'MD5 check failed'
1b7c57aab2c61f845219723b8558bea6 bodies
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`"
test 44 -eq "$shar_count" ||
$echo 'bodies:' 'original size' '44,' 'current size' "$shar_count!"
fi
fi
# ============= page01.pre ==============
if test -f 'page01.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page01.pre' '(file already exists)'
else
$echo 'x -' extracting 'page01.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page01.pre' &&
The ACE_Barrier implements the barrier synchronization pattern.
<P>
That's nice. What does it mean?
<P>
What it means is that you can use the ACE_Barrier to cause a set of
threads to all wait at a specific point in your application. In other
words: the threads reach a barrier that none can pass until all are
present.
<P>
This would typically be used in scientific applications where a set of
threads are all working in parallel on some great computation but they
have to synch and summarize before continuing to the next stage of calculation. With
proper use of ACE_Barrier, the threads can easily synch before
continuing.
<P>
In this tutorial I'll create a simple wrapper for the ACE_Barrier. In
reality, the ACE_Barrier is so easy that a wrapper isn't really
needed. I created the wrapper anyway though just because I wanted to.
SHAR_EOF
$shar_touch -am 1110144198 'page01.pre' &&
chmod 0664 'page01.pre' ||
$echo 'restore of' 'page01.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page01.pre:' 'MD5 check failed'
30840e2b3e8bf84d94abb9177bffbbec page01.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`"
test 843 -eq "$shar_count" ||
$echo 'page01.pre:' 'original size' '843,' 'current size' "$shar_count!"
fi
fi
# ============= page02.pre ==============
if test -f 'page02.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page02.pre' '(file already exists)'
else
$echo 'x -' extracting 'page02.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page02.pre' &&
First, lets take a look at the main() routine and how it will use the
Barrier wrapper class. A simple ACE_Task derivative is used so that
we can perform work in multiple threads. These threads will use the
barrier to synch in a couple of places.
<P>
Obviously this isn't a very realistic example but you should be able
to get the idea of how to use a Barrier without getting hung up in
application-level details.
<HR>
SHAR_EOF
$shar_touch -am 1110144198 'page02.pre' &&
chmod 0664 'page02.pre' ||
$echo 'restore of' 'page02.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page02.pre:' 'MD5 check failed'
72dd8d286e36d8911945824bf2c91cc3 page02.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`"
test 419 -eq "$shar_count" ||
$echo 'page02.pre:' 'original size' '419,' 'current size' "$shar_count!"
fi
fi
# ============= page03.pre ==============
if test -f 'page03.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page03.pre' '(file already exists)'
else
$echo 'x -' extracting 'page03.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page03.pre' &&
The Barrier class used by the test task is a simple wrapper around
ACE_Barrier. One of the things about ACE_Barrier is that you have to
tell it how many threads it will be managing. Since that number
usually isn't known when you create your Task derivative, you have to
dynamically allocate the ACE_Barrier. My Barrier wrapper takes care
of that for you and even provides for a clean way to delete the
ACE_Barrier instance if you want to save a few bytes.
<P>
An interesting extension of this Barrier class would be to wrap it up
in a smart pointer. You could then have the Barrier destructor invoke
wait() as a now-protected method. The result would allow you to treat
the Barrier object almost as a "synchronization guard".
<HR>
SHAR_EOF
$shar_touch -am 1110144198 'page03.pre' &&
chmod 0664 'page03.pre' ||
$echo 'restore of' 'page03.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page03.pre:' 'MD5 check failed'
6fc63f76eb4ac94dd6a8b45393613e7c page03.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`"
test 739 -eq "$shar_count" ||
$echo 'page03.pre:' 'original size' '739,' 'current size' "$shar_count!"
fi
fi
# ============= page04.pre ==============
if test -f 'page04.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page04.pre' '(file already exists)'
else
$echo 'x -' extracting 'page04.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page04.pre' &&
The Barrier implementation is quite simple. The threads() mutator
took a couple of tries to get right. In particular, be sure you know
when to apply the _wait paramter and when not to! In fact, the
requirement that only the "owning" thread can change the thread count
is rather limiting. A more appropriate solution would allow any
thread to safely change the count but that would require more complex
locking that is just a bit more than what I wanted to present here.
<HR>
SHAR_EOF
$shar_touch -am 1110144198 'page04.pre' &&
chmod 0664 'page04.pre' ||
$echo 'restore of' 'page04.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page04.pre:' 'MD5 check failed'
bed05089cb64c075cceec277e2a7da5f page04.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`"
test 478 -eq "$shar_count" ||
$echo 'page04.pre:' 'original size' '478,' 'current size' "$shar_count!"
fi
fi
# ============= page05.pre ==============
if test -f 'page05.pre' && test "$first_param" != -c; then
$echo 'x -' SKIPPING 'page05.pre' '(file already exists)'
else
$echo 'x -' extracting 'page05.pre' '(text)'
sed 's/^X//' << 'SHAR_EOF' > 'page05.pre' &&
Well, that's it for the simple Barrier Tutorial. I encourage you to
try it out and see what you like and dislike. Any improvements or
enhancements will gladly be integrated into the Tutorial.
<P>
<UL>
<LI><A HREF="Makefile">Makefile</A>
<LI><A HREF="barrier.cpp">barrier.cpp</A>
<LI><A HREF="Barrier_i.h">Barrier_i.h</A>
<LI><A HREF="Barrier_i.cpp">Barrier_i.cpp</A>
</UL>
SHAR_EOF
$shar_touch -am 1110144198 'page05.pre' &&
chmod 0664 'page05.pre' ||
$echo 'restore of' 'page05.pre' 'failed'
if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \
&& ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then
md5sum -c << SHAR_EOF >/dev/null 2>&1 \
|| $echo 'page05.pre:' 'MD5 check failed'
616a2293adddb11896d28c7172436a65 page05.pre
SHAR_EOF
else
shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`"
test 375 -eq "$shar_count" ||
$echo 'page05.pre:' 'original size' '375,' 'current size' "$shar_count!"
fi
fi
rm -fr _sh01874
exit 0
|
