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author | Johnathan Corgan | 2010-04-26 23:14:12 -0700 |
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committer | Johnathan Corgan | 2010-04-26 23:14:12 -0700 |
commit | c6ad778bda302a9abfe3f1a905d1a80ee34c60a6 (patch) | |
tree | 26cd9a62b04dc6aa9f55ff5355ff4aef45cfd762 /docs | |
parent | ac2b84b93cad94f9a8830eeb5e62dace997c9a47 (diff) | |
download | gnuradio-c6ad778bda302a9abfe3f1a905d1a80ee34c60a6.tar.gz gnuradio-c6ad778bda302a9abfe3f1a905d1a80ee34c60a6.tar.bz2 gnuradio-c6ad778bda302a9abfe3f1a905d1a80ee34c60a6.zip |
Remove omnithreads library.
Diffstat (limited to 'docs')
-rw-r--r-- | docs/doxygen/other/Makefile.am | 5 | ||||
-rw-r--r-- | docs/doxygen/other/omnithread.html | 411 | ||||
-rw-r--r-- | docs/doxygen/other/omnithread.pdf | bin | 44848 -> 0 bytes | |||
-rw-r--r-- | docs/doxygen/other/omnithread.ps | 730 |
4 files changed, 1 insertions, 1145 deletions
diff --git a/docs/doxygen/other/Makefile.am b/docs/doxygen/other/Makefile.am index 5e05d5d36..eb5f170af 100644 --- a/docs/doxygen/other/Makefile.am +++ b/docs/doxygen/other/Makefile.am @@ -1,5 +1,5 @@ # -# Copyright 2001,2004 Free Software Foundation, Inc. +# Copyright 2001,2004,2010 Free Software Foundation, Inc. # # This file is part of GNU Radio # @@ -24,9 +24,6 @@ include $(top_srcdir)/Makefile.common EXTRA_DIST = \ doxypy.py \ group_defs.dox \ - omnithread.html \ - omnithread.pdf \ - omnithread.ps \ shared_ptr_docstub.h \ tv-channel-frequencies \ vector_docstub.h diff --git a/docs/doxygen/other/omnithread.html b/docs/doxygen/other/omnithread.html deleted file mode 100644 index 5682d1d0b..000000000 --- a/docs/doxygen/other/omnithread.html +++ /dev/null @@ -1,411 +0,0 @@ -<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" - "http://www.w3.org/TR/REC-html40/loose.dtd"> -<HTML> -<HEAD><TITLE>The OMNI Thread Abstraction</TITLE> - -<META http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> -<META name="GENERATOR" content="hevea 1.06"> -</HEAD> -<BODY > -<!--HEVEA command line is: /usr/local/bin/hevea omnithread --> -<!--HTMLHEAD--> -<!--ENDHTML--> -<!--PREFIX <ARG ></ARG>--> -<!--CUT DEF section 1 --> - - -<H1 ALIGN=center>The OMNI Thread Abstraction</H1> - -<H3 ALIGN=center>Tristan Richardson<BR> -AT&T Laboratories Cambridge<BR> -</H3> - -<H3 ALIGN=center><I>Revised</I> November 2001</H3> -<!--TOC section Introduction--> - -<H2><A NAME="htoc1">1</A> Introduction</H2><!--SEC END --> - -The OMNI thread abstraction is designed to provide a common set of -thread operations for use in programs written in C++. Programs -written using the abstraction should be much easier to port between -different architectures with different underlying threads primitives.<BR> -<BR> -The programming interface is designed to be similar to the C language -interface to POSIX threads (IEEE draft standard 1003.1c --- previously -1003.4a, often known as ``pthreads'' [<A HREF="#pthreads"><CITE>POSIX94</CITE></A>]).<BR> -<BR> -Much of the abstraction consists of simple C++ object wrappers around -pthread calls. However for some features such as thread-specific -data, a better interface can be offered because of the use of C++.<BR> -<BR> -Some of the more complex features of pthreads are not supported -because of the difficulty of ensuring the same features can be offered -on top of other thread systems. Such features include thread -cancellation and complex scheduling control (though simple thread -priorities are supported).<BR> -<BR> -The abstraction layer is currently implemented for the following -architectures / thread systems: -<UL><LI>Solaris 2.x using pthreads draft 10 -<LI>Solaris 2.x using solaris threads (but pthreads version is now standard) -<LI>Alpha OSF1 using pthreads draft 4 -<LI>Windows NT using NT threads -<LI>Linux 2.x using Linuxthread 0.5 (which is based on pthreads draft 10) -<LI>Linux 2.x using MIT pthreads (which is based on draft 8) -<LI>ATMos using pthreads draft 6 (but not Virata ATMos)</UL> -See the <TT>omnithread.h</TT> header file for full details of the API. -The descriptions below assume you have some previous knowledge of -threads, mutexes, condition variables and semaphores. Also refer to -other documentation ([<A HREF="#birrell"><CITE>Birrell89</CITE></A>], [<A HREF="#pthreads"><CITE>POSIX94</CITE></A>]) for further -explanation of these ideas (particularly condition variables, the use -of which may not be particularly intuitive when first encountered).<BR> -<BR> -<!--TOC section Synchronisation objects--> - -<H2><A NAME="htoc2">2</A> Synchronisation objects</H2><!--SEC END --> - -Synchronisation objects are used to synchronise threads within the -same process. There is no inter-process synchronisation provided. -The synchronisation objects provided are mutexes, condition variables -and counting semaphores.<BR> -<BR> -<!--TOC subsection Mutex--> - -<H3><A NAME="htoc3">2.1</A> Mutex</H3><!--SEC END --> - -An object of type <TT>omni_mutex</TT> is used for mutual exclusion. -It provides two operations, <TT>lock()</TT> and <TT>unlock()</TT>. -The alternative names <TT>acquire()</TT> and <TT>release()</TT> can be -used if preferred. Behaviour is undefined when a thread attempts to -lock the same mutex again or when a mutex is locked by one thread and -unlocked by a different thread.<BR> -<BR> -<!--TOC subsection Condition Variable--> - -<H3><A NAME="htoc4">2.2</A> Condition Variable</H3><!--SEC END --> - -A condition variable is represented by an <TT>omni_condition</TT> and -is used for signalling between threads. A call to <TT>wait()</TT> -causes a thread to wait on the condition variable. A call to -<TT>signal()</TT> wakes up at least one thread if any are waiting. A -call to <TT>broadcast()</TT> wakes up all threads waiting on the -condition variable.<BR> -<BR> -When constructed, a pointer to an <TT>omni_mutex</TT> must be given. -A condition variable <TT>wait()</TT> has an implicit mutex -<TT>unlock()</TT> and <TT>lock()</TT> around it. The link between -condition variable and mutex lasts for the lifetime of the condition -variable (unlike pthreads where the link is only for the duration of -the wait). The same mutex may be used with several condition -variables.<BR> -<BR> -A wait with a timeout can be achieved by calling -<TT>timed_wait()</TT>. This is given an absolute time to wait until. -The routine <TT>omni_thread::get_time()</TT> can be used to turn a -relative time into an absolute time. <TT>timed_wait()</TT> returns -<TT>true</TT> if the condition was signalled, <TT>false</TT> if the -time expired before the condition variable was signalled.<BR> -<BR> -<!--TOC subsection Counting semaphores--> - -<H3><A NAME="htoc5">2.3</A> Counting semaphores</H3><!--SEC END --> - -An <TT>omni_semaphore</TT> is a counting semaphore. When created it -is given an initial unsigned integer value. When <TT>wait()</TT> is -called, the value is decremented if non-zero. If the value is zero -then the thread blocks instead. When <TT>post()</TT> is called, if -any threads are blocked in <TT>wait()</TT>, exactly one thread is -woken. If no threads were blocked then the value of the semaphore is -incremented.<BR> -<BR> -If a thread calls <TT>try_wait()</TT>, then the thread won't block if -the semaphore's value is 0, returning <TT>false</TT> instead.<BR> -<BR> -There is no way of querying the value of the semaphore.<BR> -<BR> -<!--TOC section Thread object--> - -<H2><A NAME="htoc6">3</A> Thread object</H2><!--SEC END --> - -A thread is represented by an <TT>omni_thread</TT> object. There are -broadly two different ways in which it can be used.<BR> -<BR> -The first way is simply to create an <TT>omni_thread</TT> object, -giving a particular function which the thread should execute. This is -like the POSIX (or any other) C language interface.<BR> -<BR> -The second method of use is to create a new class which inherits from -<TT>omni_thread</TT>. In this case the thread will execute the -<TT>run()</TT> member function of the new class. One advantage of -this scheme is that thread-specific data can be implemented simply by -having data members of the new class.<BR> -<BR> -When constructed a thread is in the "new" state and has not actually -started. A call to <TT>start()</TT> causes the thread to begin -executing. A static member function <TT>create()</TT> is provided to -construct and start a thread in a single call. A thread exits by -calling <TT>exit()</TT> or by returning from the thread function.<BR> -<BR> -Threads can be either detached or undetached. Detached threads are -threads for which all state will be lost upon exit. Other threads -cannot determine when a detached thread will disappear, and therefore -should not attempt to access the thread object unless some explicit -synchronisation with the detached thread guarantees that it still -exists.<BR> -<BR> -Undetached threads are threads for which storage is not reclaimed -until another thread waits for its termination by calling -<TT>join()</TT>. An exit value can be passed from an undetached -thread to the thread which joins it.<BR> -<BR> -Detached / undetached threads are distinguished on creation by the -type of function they execute. Undetached threads execute a function -which has a <TT>void*</TT> return type, whereas detached threads -execute a function which has a <TT>void</TT> return type. -Unfortunately C++ member functions are not allowed to be distinguished -simply by their return type. Thus in the case of a derived class of -<TT>omni_thread</TT> which needs an undetached thread, the member -function executed by the thread is called <TT>run_undetached()</TT> -rather than <TT>run()</TT>, and it is started by calling -<TT>start_undetached()</TT> instead of <TT>start()</TT>.<BR> -<BR> -The abstraction currently supports three priorities of thread, but no -guarantee is made of how this will affect underlying thread -scheduling. The three priorities are <TT>PRIORITY_LOW</TT>, -<TT>PRIORITY_NORMAL</TT> and <TT>PRIORITY_HIGH</TT>. By default all -threads run at <TT>PRIORITY_NORMAL</TT>. A different priority can be -specified on thread creation, or while the thread is running using -<TT>set_priority().</TT> A thread's current priority is returned by -<TT>priority()</TT>.<BR> -<BR> -Other functions provided are <TT>self()</TT> which returns the calling -thread's <TT>omni_thread</TT> object, <TT>yield()</TT> which -requests that other threads be allowed to run, <TT>id()</TT> which -returns an integer id for the thread for use in debugging, -<TT>state()</TT>, <TT>sleep()</TT> and <TT>get_time()</TT>.<BR> -<BR> -<!--TOC section Per-thread data--> - -<H2><A NAME="htoc7">4</A> Per-thread data</H2><!--SEC END --> - -omnithread supports per-thread data, via member functions of the -<TT>omni_thread</TT> object.<BR> -<BR> -First, you must allocate a key for with the -<TT>omni_thread::allocate_key()</TT> function. Then, any object -whose class is derived from <TT>omni_thread::value_t</TT> can be -stored using the <TT>set_value()</TT> function. Values are retrieved -or removed with <TT>get_value()</TT> and <TT>remove_value()</TT> -respectively.<BR> -<BR> -When the thread exits, all per-thread data is deleted (hence the base -class with virtual destructor).<BR> -<BR> -Note that the per-thread data functions are <B>not</B> thread safe, -so although you can access one thread's storage from another thread, -there is no concurrency control. Unless you really know what you are -doing, it is best to only access per-thread data from the thread it is -attached to.<BR> -<BR> -<!--TOC section Using OMNI threads in your program--> - -<H2><A NAME="htoc8">5</A> Using OMNI threads in your program</H2><!--SEC END --> - -Obviously you need to include the <TT>omnithread.h</TT> header file in -your source code, and link in the omnithread library with your -executable. Because there is a single <TT>omnithread.h</TT> for all -platforms, certain preprocessor defines must be given as compiler -options. The easiest way to do this is to study the makefiles given -in the examples provided with this distribution. If you are to -include OMNI threads in your own development environment, these are -the necessary preprocessor defines:<BR> -<TABLE BORDER=1 CELLSPACING=0 CELLPADDING=1> -<TR><TD ALIGN=left NOWRAP>Platform</TD> -<TD ALIGN=left NOWRAP>Preprocessor Defines</TD> -</TR> -<TR><TD ALIGN=left NOWRAP>Sun Solaris 2.x</TD> -<TD ALIGN=left NOWRAP><CODE>-D__sunos__ -D__sparc__ -D__OSVERSION__=5</CODE></TD> -</TR> -<TR><TD ALIGN=left NOWRAP> </TD> -<TD ALIGN=left NOWRAP><CODE>-DSVR4 -DUsePthread -D_REENTRANT</CODE></TD> -</TR> -<TR><TD ALIGN=left NOWRAP>x86 Linux 2.0</TD> -<TD ALIGN=left NOWRAP><CODE>-D__linux__ -D__i86__ -D__OSVERSION__=2</CODE></TD> -</TR> -<TR><TD ALIGN=left NOWRAP>with linuxthreads 0.5</TD> -<TD ALIGN=left NOWRAP><CODE>-D_REENTRANT</CODE></TD> -</TR> -<TR><TD ALIGN=left NOWRAP>Digital Unix 3.2</TD> -<TD ALIGN=left NOWRAP><CODE>-D__osf1__ -D__alpha__ -D__OSVERSION__=3</CODE></TD> -</TR> -<TR><TD ALIGN=left NOWRAP> </TD> -<TD ALIGN=left NOWRAP><CODE>-D_REENTRANT</CODE></TD> -</TR> -<TR><TD ALIGN=left NOWRAP>Windows NT</TD> -<TD ALIGN=left NOWRAP><CODE>-D__NT__ -MD</CODE></TD> -</TR></TABLE><BR> -<!--TOC section Threaded I/O shutdown for Unix--> - -<H2><A NAME="htoc9">6</A> Threaded I/O shutdown for Unix</H2><!--SEC END --> - -or, how one thread should tell another thread to shut down when it -might be doing a blocking call on a socket.<BR> -<BR> -<B>If you are using omniORB, you don't need to worry about all -this, since omniORB does it for you.</B> This section is only relevant -if you are using omnithread in your own socket-based programming. It -is also seriously out of date.<BR> -<BR> -Unfortunately there doesn't seem to be a standard way of doing this -which works across all Unix systems. I have investigated the -behaviour of Solaris 2.5 and Digital Unix 3.2. On Digital Unix -everything is fine, as the obvious method using shutdown() seems to -work OK. Unfortunately on Solaris shutdown can only be used on a -connected socket, so we need devious means to get around this -limitation. The details are summarised below:<BR> -<BR> -<!--TOC subsection read()--> - -<H3><A NAME="htoc10">6.1</A> read()</H3><!--SEC END --> - -Thread A is in a loop, doing <CODE>read(sock)</CODE>, processing the data, -then going back into the read.<BR> -<BR> -Thread B comes along and wants to shut it down --- it can't cancel -thread A since (i) working out how to clean up according to where A is -in its loop is a nightmare, and (ii) this isn't available in -omnithread anyway.<BR> -<BR> -On Solaris 2.5 and Digital Unix 3.2 the following strategy works:<BR> -<BR> -Thread B does <CODE>shutdown(sock,2)</CODE>.<BR> -<BR> -At this point thread A is either blocked inside <CODE>read(sock)</CODE>, or -is elsewhere in the loop. If the former then read will return 0, -indicating that the socket is closed. If the latter then eventually -thread A will call <CODE>read(sock)</CODE> and then this will return 0. -Thread A should <CODE>close(sock)</CODE>, do any other tidying up, and exit.<BR> -<BR> -If there is another point in the loop that thread A can block then -obviously thread B needs to be aware of this and be able to wake it up -in the appropriate way from that point.<BR> -<BR> -<!--TOC subsection accept()--> - -<H3><A NAME="htoc11">6.2</A> accept()</H3><!--SEC END --> - -Again thread A is in a loop, this time doing an accept on listenSock, -dealing with a new connection and going back into accept. Thread B -wants to cancel it.<BR> -<BR> -On Digital Unix 3.2 the strategy is identical to that for read:<BR> -<BR> -Thread B does <CODE>shutdown(listenSock,2)</CODE>. Wherever thread A is in -the loop, eventually it will return <CODE>ECONNABORTED</CODE> from the -accept call. It should <CODE>close(listenSock)</CODE>, tidy up as necessary -and exit.<BR> -<BR> -On Solaris 2.5 thread B can't do <CODE>shutdown(listenSock,2)</CODE> --- -this returns <CODE>ENOTCONN</CODE>. Instead the following strategy can be -used:<BR> -<BR> -First thread B sets some sort of "shutdown flag" associated with -listenSock. Then it does <CODE>getsockaddr(listenSock)</CODE> to find out -which port listenSock is on (or knows already), sets up a socket -dummySock, does <CODE>connect(dummySock,</CODE> <CODE>this host, port)</CODE> and -finally does <CODE>close(dummySock)</CODE>.<BR> -<BR> -Wherever thread A is in the loop, eventually it will call -<CODE>accept(listenSock)</CODE>. This will return successfully with a new -socket, say connSock. Thread A then checks to see if the "shutdown -flag" is set. If not, then it's a normal connection. If it is set, -then thread A closes listenSock and connSock, tidies up and exits.<BR> -<BR> -<!--TOC subsection write()--> - -<H3><A NAME="htoc12">6.3</A> write()</H3><!--SEC END --> - -Thread A may be blocked in write, or about to go in to a -potentially-blocking write. Thread B wants to shut it down.<BR> -<BR> -On Solaris 2.5:<BR> -<BR> -Thread B does <CODE>shutdown(sock,2)</CODE>.<BR> -<BR> -If thread A is already in <CODE>write(sock)</CODE> then it will return with -<CODE>ENXIO</CODE>. If thread A calls write after thread B calls shutdown -this will return <CODE>EIO</CODE>.<BR> -<BR> -On Digital Unix 3.2:<BR> -<BR> -Thread B does <CODE>shutdown(sock,2)</CODE>.<BR> -<BR> -If thread A is already in <CODE>write(sock)</CODE> then it will return the -number of bytes written before it became blocked. A subsequent call -to write will then generate <CODE>SIGPIPE</CODE> (or <CODE>EPIPE</CODE> will be -returned if <CODE>SIGPIPE</CODE> is ignored by the thread).<BR> -<BR> -<!--TOC subsection connect()--> - -<H3><A NAME="htoc13">6.4</A> connect()</H3><!--SEC END --> - -Thread A may be blocked in connect, or about to go in to a -potentially-blocking connect. Thread B wants to shut it down.<BR> -<BR> -On Digital Unix 3.2:<BR> -<BR> -Thread B does <CODE>shutdown(sock,2)</CODE>.<BR> -<BR> -If thread A is already in <CODE>connect(sock)</CODE> then it will return a -successful connection. Subsequent reading or writing will show that -the socket has been shut down (i.e. read returns 0, write generates -<CODE>SIGPIPE</CODE> or returns <CODE>EPIPE</CODE>). If thread A calls connect -after thread B calls shutdown this will return <CODE>EINVAL</CODE>.<BR> -<BR> -On Solaris 2.5:<BR> -<BR> -There is no way to wake up a thread which is blocked in connect. -Instead Solaris forces us through a ridiculous procedure whichever way -we try it. One way is this:<BR> -<BR> -First thread A creates a pipe in addition to the socket. Instead of -shutting down the socket, thread B simply writes a byte to the pipe.<BR> -<BR> -Thread A meanwhile sets the socket to non-blocking mode using -<CODE>fcntl(sock,</CODE> <CODE>F_SETFL, O_NONBLOCK)</CODE>. Then it calls connect -on the socket --- this will return <CODE>EINPROGRESS</CODE>. Then it must -call <CODE>select()</CODE>, waiting for either sock to become writable or -for the pipe to become readable. If select returns that just sock is -writable then the connection has succeeded. It then needs to set the -socket back to blocking mode using <CODE>fcntl(sock, F_SETFL, 0)</CODE>. If -instead select returns that the pipe is readable, thread A closes the -socket, tidies up and exits.<BR> -<BR> -An alternative method is similar but to use polling instead of the -pipe. Thread B justs sets a flag and thread A calls select with a -timeout, periodically waking up to see if the flag has been set.<BR> -<BR> -<!--TOC section References--> - -<H2>References</H2><!--SEC END --> -<DL COMPACT=compact><DT><A NAME="pthreads"><FONT COLOR=purple>[POSIX94]</FONT></A><DD> -<EM>Portable Operating System Interface (POSIX) Threads Extension</EM>, -P1003.1c Draft 10, -IEEE, -September 1994.<BR> -<BR> -<DT><A NAME="birrell"><FONT COLOR=purple>[Birrell89]</FONT></A><DD> -<EM>An Introduction to Programming with Threads</EM>, -Research Report 35, -DEC Systems Research Center, -Palo Alto, CA, -January 1989.</DL> -<!--HTMLFOOT--> -<!--ENDHTML--> -<!--FOOTER--> -<HR SIZE=2> -<BLOCKQUOTE><EM>This document was translated from L<sup>A</sup>T<sub>E</sub>X by -</EM><A HREF="http://pauillac.inria.fr/~maranget/hevea/index.html"><EM>H<FONT SIZE=2><sup>E</sup></FONT>V<FONT SIZE=2><sup>E</sup></FONT>A</EM></A><EM>. -</EM></BLOCKQUOTE> -</BODY> -</HTML> diff --git a/docs/doxygen/other/omnithread.pdf b/docs/doxygen/other/omnithread.pdf Binary files differdeleted file mode 100644 index b0033072f..000000000 --- a/docs/doxygen/other/omnithread.pdf +++ /dev/null diff --git a/docs/doxygen/other/omnithread.ps b/docs/doxygen/other/omnithread.ps deleted file mode 100644 index 9e858f0b7..000000000 --- a/docs/doxygen/other/omnithread.ps +++ /dev/null @@ -1,730 +0,0 @@ -%!PS-Adobe-2.0 -%%Creator: dvipsk 5.86 p1.5d Copyright 1996-2001 ASCII Corp.(www-ptex@ascii.co.jp) -%%based on dvipsk 5.86 Copyright 1999 Radical Eye Software (www.radicaleye.com) -%%Title: omnithread.dvi -%%Pages: 7 -%%PageOrder: Ascend -%%BoundingBox: 0 0 596 842 -%%DocumentFonts: Palatino-Roman Palatino-Italic Palatino-Bold Courier -%%EndComments -%DVIPSWebPage: (www.radicaleye.com) -%DVIPSCommandLine: dvips omnithread -%DVIPSParameters: dpi=600, compressed -%DVIPSSource: TeX output 2002.08.15:1756 -%%BeginProcSet: texc.pro -%! 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f(on) g(draft) h(8\)) p Ff 199 5403 a(\017) p -Fg 46 w(A) -7 b(TMos) 22 b(using) g(pthr) n(eads) f(draft) h(6) i -(\(but) e(not) g(V) -5 b(irata) 23 b(A) -7 b(TMos\)) 1684 -5652 y(1) p 90 rotate dyy eop -%%Page: 2 2 -2 1 bop Fg 221 249 a(2) p Fe 1797 w(2) 91 b(SYNCHRONI) n(SA) -7 -b(TION) 22 b(OBJECTS) p Fg 362 548 a(See) h(the) p Fd -22 w(omni) n(thre) n(ad.h) p Fg 22 w(header) f(\002le) i(for) f(full) i -(det) n(ail) r(s) e(of) g(the) g(API.) f(The) h(des) n(criptions) 221 -661 y(below) 35 b(assume) g(you) g(have) h(some) e(pr) n(evious) h -(knowled) n(ge) g(of) h(thr) n(eads) n(,) j(mutexes) n(,) g(condi-) 221 -774 y(tion) f(varia) r(bles) g(and) g(semaphor) n(es) n(.) 75 -b(Also) 38 b(r) n(efer) f(to) h(other) f(document) n(ation) i(\([Birr) n -(ell89) r(],) 221 887 y([POSIX94) q(]\)) 22 b(for) g(further) f -(explanation) i(of) f(thes) n(e) g(ideas) g(\(particularly) h -(condition) f(variab) r(les,) 221 1000 y(the) g(use) g(of) g(which) h -(may) g(not) f(be) h(particularly) h(intuitive) f(when) f(\002rst) f -(encounter) n(ed) n(\).) p Fh 221 1299 a(2) 119 b(Synchronisation) 31 -b(objects) p Fg 221 1510 a(Synchr) n(onisation) 26 b(objects) h(ar) n -(e) g(used) e(to) h(synchr) n(onise) g(thr) n(eads) g(within) h(the) f -(same) h(pr) n(ocess) n(.) 221 1623 y(Ther) n(e) j(is) i(no) f(inter) n -(-pr) n(ocess) f(synchr) n(onisation) g(pr) n(ovided.) 53 -b(The) 30 b(synchr) n(onisation) h(objects) 221 1735 -y(pr) n(ovided) 22 b(ar) n(e) h(mutexes) n(,) g(condition) f(variab) r -(les) g(and) h(counting) f(semaphor) n(e) n(s.) p Fc -221 1991 a(2.1) 99 b(Mutex) p Fg 221 2168 a(An) 26 b(object) g(of) h -(typ) n(e) p Fd 26 w(omni) n(_mute) n(x) p Fg 26 w(is) g(use) n(d) f -(for) h(mutual) f(exclusion.) 39 b(It) 26 b(pr) n(ovides) f(two) g(op-) -221 2281 y(erations,) p Fd 37 w(lock\() n(\)) p Fg 35 -w(and) p Fd 35 w(unloc) n(k\(\)) p Fg(.) 64 b(The) 35 -b(alternative) h(names) p Fd 35 w(acq) n(uire\() n(\)) p -Fg 35 w(and) p Fd 35 w(re-) 221 2393 y(leas) n(e\(\)) p -Fg 19 w(can) 21 b(be) f(used) f(if) i(pr) n(eferr) n(ed) n(.) 27 -b(Behaviour) 20 b(is) g(unde\002ne) n(d) g(when) f(a) i(thr) n(ead) f -(attempt) n(s) 221 2506 y(to) 30 b(lock) h(the) e(same) i(mutex) f -(again) h(or) f(when) g(a) h(mutex) f(is) h(locked) e(by) i(one) e(thr) -n(ead) h(and) h(un-) 221 2619 y(locked) 22 b(by) h(a) g(dif) n(fer) n -(ent) f(thr) n(ead.) p Fc 221 2874 a(2.2) 99 b(Condition) 26 -b(V) -11 b(ariable) p Fg 221 3051 a(A) 28 b(condition) f(varia) r(ble) h -(is) g(r) n(epr) n(ese) n(nted) f(by) h(an) p Fd 28 w(omn) n(i_con) n -(diti) n(on) p Fg 27 w(and) g(is) g(used) e(for) i(sig-) 221 -3164 y(nalli) r(ng) 20 b(betwee) n(n) g(thr) n(eads.) 26 -b(A) 21 b(call) h(to) p Fd 19 w(wait\() n(\)) p Fg 20 -w(causes) e(a) h(thr) n(ead) e(to) h(wait) h(on) f(the) f(condition) 221 -3277 y(varia) r(ble.) 45 b(A) 28 b(call) i(to) p Fd 27 -w(sign) n(al\(\)) p Fg 27 w(wakes) d(up) h(at) g(least) g(one) f(thr) n -(ead) h(if) h(any) f(ar) n(e) g(waiting.) 45 b(A) 221 -3390 y(call) 25 b(to) p Fd 22 w(bro) n(adca) n(st\(\)) p -Fg 21 w(wakes) d(up) g(all) i(thr) n(eads) e(waiting) h(on) f(the) g -(condition) g(varia) r(ble.) 362 3503 y(When) 30 b(constr) o(ucte) n -(d,) i(a) e(pointer) f(to) h(an) p Fd 30 w(omni) n(_mute) n(x) p -Fg 30 w(must) f(be) h(given.) 50 b(A) 30 b(condition) 221 -3616 y(varia) r(ble) p Fd 33 w(wait\() n(\)) p Fg 33 -w(has) j(an) h(implic) r(it) f(mutex) p Fd 33 w(unlo) n(ck\(\)) p -Fg 32 w(and) p Fd 33 w(lock) n(\(\)) p Fg 33 w(ar) n(ound) g(it.) 60 -b(The) 221 3729 y(link) 30 b(between) f(condition) g(varia) r(ble) h -(and) g(mutex) f(lasts) g(for) h(the) f(lifetime) i(of) e(the) g -(condition) 221 3842 y(varia) r(ble) c(\(unlike) h(pthr) n(eads) e -(wher) n(e) g(the) h(link) h(is) f(only) g(for) g(the) g(duration) f -(of) i(the) e(wait\).) 37 b(The) 221 3955 y(same) 23 -b(mutex) f(may) h(be) f(used) f(with) i(several) f(condition) h(variab) -r(les.) 362 4068 y(A) c(wait) g(with) g(a) g(timeout) f(can) i(be) e -(achieved) h(by) g(call) r(ing) p Fd 19 w(tim) n(ed_w) n(ait\(\)) p -Fg -2 w(.) 27 b(This) 18 b(is) h(given) 221 4181 y(an) 27 -b(absolute) e(time) h(to) f(wait) h(until.) 38 b(The) 26 -b(r) n(outine) p Fd 25 w(omn) n(i_thr) n(ead:) n(:get_) n(time) n(\(\)) -p Fg 25 w(can) h(be) 221 4293 y(used) 21 b(to) h(turn) g(a) h(r) n -(elativ) r(e) f(time) g(into) h(an) g(absolute) f(time.) p -Fd 28 w(tim) n(ed_wa) n(it\(\)) p Fg 21 w(r) n(eturns) p -Fd 21 w(true) p Fg 21 w(if) 221 4406 y(the) 27 b(condition) h(was) g -(signalled,) p Fd 29 w(false) p Fg 26 w(if) h(the) f(time) g(expir) n -(ed) f(befor) n(e) g(the) h(condition) f(vari) r(-) 221 -4519 y(able) d(was) e(signalled.) p Fc 221 4774 a(2.3) 99 -b(Counting) 26 b(semaphores) p Fg 221 4951 a(An) p Fd -21 w(omn) n(i_sem) n(apho) n(re) p Fg 20 w(is) 21 b(a) h(counting) e -(semaphor) n(e) n(.) 28 b(When) 20 b(cr) n(eated) g(it) h(is) g(given) g -(an) g(initial) 221 5064 y(unsigned) j(intege) n(r) i(value.) 36 -b(When) p Fd 25 w(wai) n(t\(\)) p Fg 24 w(is) 26 b(called,) g(the) f -(value) h(is) f(decr) n(emente) n(d) g(if) h(non-) 221 -5177 y(zer) n(o.) 43 b(If) 27 b(the) g(value) h(is) f(zer) n(o) h(then) -f(the) f(thr) n(ead) h(blocks) h(instead.) 41 b(When) p -Fd 27 w(post) n(\(\)) p Fg 27 w(is) 27 b(cal) r(led,) 221 -5290 y(if) h(any) g(thr) n(eads) e(ar) n(e) i(blocked) f(in) p -Fd 27 w(wait\() n(\)) p Fg(,) h(exactly) f(one) g(thr) n(ead) g(is) g -(woken.) 41 b(If) 27 b(no) g(thr) n(eads) 221 5403 y(wer) n(e) 22 -b(blocked) g(then) g(the) g(value) h(of) g(the) e(semaphor) n(e) h(is) h -(incr) n(emented.) p 90 rotate dyy eop -%%Page: 3 3 -3 2 bop Fg 3306 249 a(3) 204 548 y(If) 27 b(a) h(thr) n(ead) e(cal) r -(ls) p Fd 27 w(try) n(_wait) n(\(\)) p Fg(,) h(then) g(the) f(thr) n -(ead) g(won't) h(block) h(if) f(the) g(semaphor) n(e's) 63 -661 y(value) c(is) g(0,) g(r) n(eturning) p Fd 21 w(false) p -Fg 21 w(instead.) 204 777 y(Ther) n(e) f(is) g(no) h(way) f(of) h -(query) n(ing) g(the) f(value) h(of) g(the) f(semaphor) n(e) n(.) p -Fh 63 1095 a(3) 119 b(Thread) 29 b(object) p Fg 63 1313 -a(A) 23 b(thr) n(ead) g(is) h(r) n(epr) n(ese) n(nted) e(by) i(an) p -Fd 24 w(omni) n(_thr) n(ead) p Fg 23 w(object.) 30 b(Ther) n(e) 23 -b(ar) n(e) h(br) n(oadly) g(two) e(dif) n(fer) n(-) 63 -1426 y(ent) f(ways) i(in) g(which) g(it) g(can) g(be) g(used) n(.) 204 -1542 y(The) 28 b(\002rst) g(way) h(is) h(simply) f(to) f(cr) n(eate) h -(an) p Fd 30 w(omn) n(i_thr) n(ead) p Fg 28 w(object,) h(giving) g(a) f -(particula) r(r) 63 1655 y(function) c(which) h(the) e(thr) n(ead) h -(should) f(execute) n(.) 36 b(This) 25 b(is) g(like) g(the) g(POSIX) f -(\(or) i(any) f(other) n(\)) h(C) 63 1768 y(language) c(interface.) 204 -1884 y(The) k(second) f(method) h(of) h(use) e(is) i(to) f(cr) n(eate) h -(a) g(new) g(class) g(which) g(inherits) f(fr) n(om) p -Fd 28 w(omn) n(i_) 63 1997 y(thr) n(ead) p Fg(.) 50 b(In) 31 -b(this) f(case) g(the) g(thr) n(ead) g(will) i(execute) d(the) p -Fd 29 w(run\(\)) p Fg 29 w(member) h(function) h(of) f(the) 63 -2109 y(new) 22 b(class.) 29 b(One) 23 b(advantage) g(of) g(this) g -(scheme) f(is) h(that) g(thr) n(ead-speci\002c) g(data) g(can) h(be) f -(imple-) 63 2222 y(mented) e(simply) h(by) h(having) g(data) g(members) -f(of) h(the) f(new) g(class.) 204 2339 y(When) f(constr) o(ucted) g(a) i -(thr) n(ead) f(is) g(in) h(the) e("new") h(state) f(and) h(has) g(not) g -(actuall) r(y) g(starte) n(d.) 28 b(A) 63 2451 y(call) j(to) p -Fd 29 w(sta) n(rt\(\)) p Fg 28 w(causes) e(the) g(thr) n(ead) g(to) g -(begin) g(executing.) 47 b(A) 29 b(static) h(member) f(function) p -Fd 63 2564 a(cre) n(ate\() n(\)) p Fg 32 w(is) j(pr) n(ovided) f(to) g -(constr) o(uct) g(and) g(start) g(a) i(thr) n(ead) e(in) h(a) g(single) -g(call.) 57 b(A) 31 b(thr) n(ead) 63 2677 y(exits) 21 -b(by) i(call) r(ing) p Fd 22 w(exit\() n(\)) p Fg 22 -w(or) g(by) f(r) n(eturning) g(fr) n(om) h(the) f(thr) n(ead) g -(function.) 204 2793 y(Thr) n(eads) 27 b(can) j(be) e(either) g -(detached) f(or) h(undetached) n(.) 46 b(Detached) 28 -b(thr) n(eads) g(ar) n(e) h(thr) n(eads) 63 2906 y(for) h(which) i(all) -g(state) e(will) i(be) f(lost) f(upon) g(exit.) 52 b(Other) 30 -b(thr) n(eads) g(cannot) h(dete) n(rmine) g(when) 63 -3019 y(a) e(detached) f(thr) n(ead) h(will) h(disappear) -7 -b(,) 31 b(and) e(ther) n(efor) n(e) f(should) g(not) h(attempt) f(to) g -(access) h(the) 63 3132 y(thr) n(ead) 23 b(object) g(unless) f(some) h -(explicit) h(synchr) n(onisation) f(with) g(the) g(detached) f(thr) n -(ead) h(guar) n(-) 63 3245 y(antees) e(that) h(it) h(still) g(exists.) -204 3361 y(Undet) n(ached) 33 b(thr) n(eads) f(ar) n(e) i(thr) n(eads) e -(for) h(which) g(storage) f(is) h(not) f(r) n(eclai) r(med) g(until) i -(an-) 63 3474 y(othe) n(r) g(thr) n(ead) g(waits) g(for) g(its) g -(termination) g(by) g(call) r(ing) p Fd 34 w(joi) n(n\(\)) p -Fg(.) 61 b(An) 34 b(exit) g(value) h(can) g(be) 63 3587 -y(passe) n(d) 23 b(fr) n(om) g(an) g(undet) n(ached) g(thr) n(ead) f -(to) g(the) g(thr) n(ead) g(which) h(joins) g(it.) 204 -3703 y(Detached) 31 b(/) h(undetached) e(thr) n(eads) h(ar) n(e) i -(distinguish) n(ed) f(on) f(cr) n(eation) h(by) g(the) f(type) g(of) 63 -3816 y(function) 24 b(they) e(execute.) 30 b(Undetached) 22 -b(thr) n(eads) h(execute) g(a) h(function) g(which) g(has) g(a) p -Fd 25 w(voi) n(d*) p Fg 63 3929 a(r) n(eturn) c(typ) n(e,) h(wher) n -(eas) f(detached) f(thr) n(eads) h(execute) f(a) j(function) f(which) g -(has) g(a) p Fd 21 w(void) p Fg 19 w(r) n(eturn) 63 4042 -y(typ) n(e.) 52 b(Unfortunate) n(ly) 31 b(C++) g(member) g(functions) f -(ar) n(e) h(not) f(allowed) g(to) g(be) h(distingu) n(ished) 63 -4155 y(simply) 26 b(by) h(their) f(r) n(eturn) g(type) n(.) 40 -b(Thus) 26 b(in) h(the) f(case) h(of) g(a) g(derived) f(class) h(of) p -Fd 26 w(omni_) n(thre) n(ad) p Fg 63 4268 a(which) 20 -b(needs) e(an) j(undet) n(ached) f(thr) n(ead,) g(the) f(member) h -(function) g(execute) n(d) g(by) g(the) f(thr) n(ead) g(is) 63 -4380 y(called) p Fd 19 w(run_u) n(ndet) n(ache) n(d\(\)) p -Fg 18 w(rather) f(than) p Fd 19 w(run\() n(\)) p Fg(,) h(and) g(it) g -(is) g(started) e(by) i(calli) r(ng) p Fd 18 w(star) n(t_) 63 -4493 y(und) n(etac) n(hed\(\)) p Fg 21 w(instead) j(of) p -Fd 22 w(start) n(\(\)) p Fg(.) 204 4610 y(The) i(abstraction) i(curr) n -(ently) e(suppo) n(rts) h(thr) n(ee) f(priorities) g(of) h(thr) n(ead,) -g(but) g(no) g(guarantee) 63 4722 y(is) 33 b(made) g(of) h(how) f(this) -g(will) h(af) n(f) r(ect) f(underlying) f(thr) n(ead) h(scheduling.) 59 -b(The) 33 b(thr) n(ee) f(priori-) 63 4835 y(ties) 18 -b(ar) n(e) p Fd 20 w(PRIO) n(RITY) n(_LOW) p Fg(,) p -Fd 18 w(PRIO) n(RITY) n(_NOR) n(MAL) p Fg 19 w(and) p -Fd 19 w(PRIO) n(RITY) n(_HIG) n(H) p Fg(.) h(By) g(default) g(all) 63 -4948 y(thr) n(eads) i(r) o(un) i(at) p Fd 23 w(PRIO) n(RITY) n(_NORM) n -(AL) p Fg(.) f(A) g(dif) n(fer) n(ent) h(priority) f(can) i(be) e -(speci\002ed) g(on) g(thr) n(ead) 63 5061 y(cr) n(eation,) h(or) f -(while) h(the) f(thr) n(ead) g(is) h(r) o(unning) g(using) p -Fd 22 w(set_) n(prio) n(rity\() n(\).) p Fg 28 w(A) g(thr) n(ead's) f -(cur) n(-) 63 5174 y(r) n(ent) g(priority) g(is) g(r) n(eturned) f(by) p -Fd 23 w(pri) n(ority) n(\(\)) p Fg(.) 204 5290 y(Other) d(functions) g -(pr) n(ovided) g(ar) n(e) p Fd 19 w(sel) n(f\(\)) p Fg -18 w(which) h(r) n(eturns) e(the) h(calli) r(ng) g(thr) n(ead's) p -Fd 18 w(omn) n(i_) 63 5403 y(thr) n(ead) p Fg 36 w(object,) p -Fd 40 w(yie) n(ld\(\)) p Fg 35 w(which) 38 b(r) n(eques) n(ts) e(that) h -(other) e(thr) n(eads) h(be) h(allowed) g(to) f(r) o(un,) p -90 rotate dyy eop -%%Page: 4 4 -4 3 bop Fg 221 249 a(4) p Fe 1367 w(6) 91 b(THRE) n(ADED) 23 -b(I/O) g(SHUTDOWN) f(FOR) g(UNIX) p Fd 221 548 a(id\(\)) p -Fg 27 w(which) 29 b(r) n(eturns) e(an) i(intege) n(r) g(id) f(for) h -(the) e(thr) n(ead) h(for) g(use) g(in) h(debug) n(ging,) p -Fd 29 w(state) n(\(\)) p Fg(,) p Fd 221 661 a(slee) n(p\(\)) p -Fg 22 w(and) p Fd 22 w(get_t) n(ime\() n(\)) p Fg(.) p -Fh 221 953 a(4) 119 b(Per) n(-threa) n(d) 30 b(data) p -Fg 221 1164 a(omnithr) n(ead) 22 b(suppo) n(rts) g(per) n(-thr) n(ead) f -(data,) h(via) i(member) e(functions) f(of) i(the) p -Fd 21 w(omni) n(_thr) n(ead) p Fg 221 1277 a(object.) 362 -1390 y(First,) d(you) g(must) h(allocate) h(a) f(key) f(for) g(with) h -(the) p Fd 20 w(omni) n(_thre) n(ad::) n(allo) n(cate_) n(key\() n(\)) p -Fg 221 1502 a(function.) 28 b(Then,) 21 b(any) h(object) g(whose) f -(class) h(is) g(derived) f(fr) n(om) p Fd 23 w(omni) n(_thr) n(ead::) n -(valu) n(e_t) p Fg 221 1615 a(can) 27 b(be) f(stor) n(e) n(d) g(using) f -(the) p Fd 26 w(set) n(_val) n(ue\(\)) p Fg 25 w(function.) 38 -b(V) -8 b(alues) 25 b(ar) n(e) h(r) n(etrieved) f(or) h(r) n(emoved) 221 -1728 y(with) p Fd 23 w(get) n(_valu) n(e\(\)) p Fg 21 -w(and) p Fd 23 w(remo) n(ve_v) n(alue\() n(\)) p Fg 22 -w(r) n(espectively) -10 b(.) 362 1841 y(When) 23 b(the) g(thr) n(ead) g -(exits,) g(all) i(per) n(-thr) n(ead) e(data) h(is) g(delet) n(ed) f -(\(hence) h(the) e(base) i(class) g(with) 221 1954 y(virtual) g(dest) n -(r) o(uctor\).) 362 2067 y(Note) 17 b(that) i(the) f(per) n(-thr) n -(ead) f(data) i(functions) f(ar) n(e) p Fb 19 w(not) p -Fg 18 w(thr) n(ead) g(safe,) i(so) d(although) i(you) e(can) 221 -2180 y(access) 29 b(one) e(thr) n(ead's) h(storage) f(fr) n(om) i -(another) f(thr) n(ead,) h(ther) n(e) e(is) i(no) f(concurr) n(ency) g -(contr) n(ol.) 221 2293 y(Unless) j(you) g(r) n(eall) r(y) h(know) f -(what) h(you) f(ar) n(e) i(doing,) g(it) g(is) f(best) f(to) h(only) g -(access) g(per) n(-thr) n(ead) 221 2406 y(data) 23 b(fr) n(om) g(the) f -(thr) n(ead) g(it) h(is) g(attached) f(to.) p Fh 221 -2698 a(5) 119 b(Using) 31 b(OMNI) d(threads) h(in) h(your) g(program) p -Fg 221 2909 a(Obvi) r(ously) 16 b(you) h(need) g(to) g(include) h(the) p -Fd 16 w(omnit) n(hrea) n(d.h) p Fg 17 w(header) e(\002le) i(in) g(your) -f(sour) n(ce) g(code,) 221 3021 y(and) 25 b(link) g(in) h(the) e -(omnithr) n(ead) g(libra) r(ry) g(with) h(your) f(execut) n(abl) r(e.) -34 b(Because) 23 b(ther) n(e) h(is) h(a) g(single) p -Fd 221 3134 a(omni) n(threa) n(d.h) p Fg 30 w(for) 32 -b(all) h(platforms,) h(certain) e(pr) n(epr) n(oces) n(sor) f -(de\002nes) f(must) h(be) g(given) h(as) 221 3247 y(compiler) 25 -b(options) n(.) 33 b(The) 23 b(easiest) g(way) h(to) g(do) f(this) h -(is) g(to) g(stud) n(y) g(the) g(make\002les) f(given) h(in) h(the) 221 -3360 y(examples) i(pr) n(ovided) g(with) g(this) g(distribution.) 42 -b(If) 27 b(you) g(ar) n(e) g(to) g(include) h(OMNI) f(thr) n(eads) g -(in) 221 3473 y(your) 18 b(own) g(development) g(envir) n(onment,) h -(thes) n(e) g(ar) n(e) g(the) f(necessary) g(pr) n(epr) n(oce) n(ssor) g -(de\002nes) n(:) p 362 3567 3287 4 v 360 3680 4 113 v -412 3646 a(Platform) p 1312 3680 V 599 w(Pr) n(epr) n(ocess) n(or) 23 -b(De\002nes) p 3648 3680 V 362 3683 3287 4 v 362 3700 -V 360 3813 4 113 v 412 3779 a(Sun) f(Solaris) h(2.x) p -1312 3813 V Fd 365 w(-D__) n(suno) n(s__) 54 b(-D_) n(_spa) n(rc__) f -(-D__) n(OSVER) n(SION) n(__=5) p 3648 3813 V 360 3926 -V 1312 3926 V 1363 3892 a(-DSV) n(R4) h(-DUs) n(ePth) n(read) f(-D_R) n -(EENT) n(RANT) p 3648 3926 V 362 3929 3287 4 v 360 4042 -4 113 v Fg 412 4008 a(x86) 24 b(Linux) e(2.0) p 1312 -4042 V Fd 418 w(-D__) n(linu) n(x__) 54 b(-D_) n(_i86) n(__) g(-D__) n -(OSVE) n(RSION) n(__=2) p 3648 4042 V 360 4155 V Fg 412 -4121 a(with) 23 b(linuxthr) n(eads) f(0.5) p 1312 4155 -V Fd 100 w(-D_R) n(EENT) n(RANT) p 3648 4155 V 362 4158 -3287 4 v 360 4271 4 113 v Fg 412 4237 a(Digital) i(Unix) f(3.2) p -1312 4271 V Fd 320 w(-D__) n(osf1) n(__) 54 b(-D__) n(alph) n(a__) g -(-D_) n(_OSV) n(ERSIO) n(N__=) n(3) p 3648 4271 V 360 -4384 V 1312 4384 V 1363 4350 a(-D_R) n(EENT) n(RANT) p -3648 4384 V 362 4387 3287 4 v 360 4500 4 113 v Fg 412 -4466 a(W) -5 b(indows) 22 b(NT) p 1312 4500 V Fd 411 -w(-D__) n(NT__) 53 b(-MD) p 3648 4500 V 362 4503 3287 -4 v Fh 221 4740 a(6) 119 b(Threaded) 29 b(I/O) g(shutdown) h(for) g -(Unix) p Fg 221 4951 a(or) -7 b(,) 20 b(how) e(one) g(thr) n(ead) h -(shou) n(ld) h(tell) f(another) f(thr) n(ead) g(to) h(shut) f(down) g -(when) g(it) h(might) g(be) g(doing) 221 5064 y(a) k(blocking) g(cal) r -(l) g(on) f(a) h(socket) n(.) p Fb 362 5177 a(If) h(you) e(are) i -(using) e(omniOR) n(B,) h(you) e(don') n(t) i(need) g(to) g(worry) f -(about) g(all) i(this,) f(since) h(om-) 221 5290 y(niORB) i(does) h(it) -h(for) f(you) n(.) p Fg 41 w(This) g(section) f(is) h(only) g(r) n -(elevant) g(if) h(you) e(ar) n(e) h(using) f(omnithr) n(ead) 221 -5403 y(in) d(your) f(own) g(socket) n(-based) h(pr) n(ogramming.) k(It) -22 b(is) h(also) g(serious) n(ly) g(out) f(of) h(date.) p -90 rotate dyy eop -%%Page: 5 5 -5 4 bop Fe 63 249 a(6.1) 91 b(r) n(ead\(\)) p Fg 2800 -w(5) 204 548 y(Unfortunate) n(ly) 35 b(ther) n(e) e(doe) n(sn't) h -(seem) f(to) h(be) g(a) h(standar) n(d) e(way) i(of) f(doing) f(this) h -(which) 63 661 y(works) 19 b(acr) n(oss) i(all) i(Unix) e(syst) n(ems.) -27 b(I) 21 b(have) g(investigated) f(the) h(behaviour) g(of) g(Solaris) -h(2.5) g(and) 63 774 y(Digital) k(Unix) g(3.2.) 36 b(On) 26 -b(Digital) h(Unix) e(everyth) n(ing) h(is) f(\002ne,) g(as) h(the) e -(obvious) h(method) f(using) 63 887 y(shutd) n(own\(\)) 32 -b(seems) f(to) h(work) f(OK.) h(Unfortunately) f(on) h(Solaris) h(shut) -n(down) f(can) h(only) f(be) 63 1000 y(used) 25 b(on) h(a) h(connected) -e(socke) n(t,) i(so) f(we) g(need) f(devious) h(means) g(to) g(get) f -(ar) n(ound) h(this) g(lim) r(ita-) 63 1112 y(tion.) h(The) 22 -b(details) g(ar) n(e) h(summarised) g(below:) p Fc 63 -1429 a(6.1) 99 b(read\(\)) p Fg 63 1627 a(Thr) n(ead) 28 -b(A) h(is) g(in) h(a) g(loop,) g(doing) p Fd 28 w(rea) n(d\(soc) n(k\)) -p Fg(,) g(pr) n(ocess) n(ing) f(the) g(data,) h(then) f(going) f(back) -63 1739 y(into) 22 b(the) g(r) n(ead.) 204 1862 y(Thr) n(ead) 30 -b(B) h(comes) f(along) h(and) g(wants) f(to) g(shut) g(it) h(down) f -(\227) h(it) g(can't) g(cancel) h(thr) n(ead) f(A) 63 -1975 y(since) 21 b(\(i\)) h(working) e(out) g(how) g(to) h(clean) h(up) -e(accor) n(ding) i(to) e(wher) n(e) g(A) h(is) g(in) h(its) f(loop) f -(is) h(a) h(night-) 63 2088 y(mar) n(e,) h(and) f(\(ii\)) i(this) f -(isn't) f(ava) r(ilabl) r(e) g(in) h(omnithr) n(ead) f(anyway) -10 -b(.) 204 2211 y(On) 23 b(Solaris) g(2.5) g(and) g(Digital) h(Unix) f -(3.2) g(the) f(following) h(strate) n(gy) f(works:) 204 -2334 y(Thr) n(ead) g(B) g(does) p Fd 21 w(shut) n(down\() n(sock) n -(,2\)) p Fg(.) 204 2457 y(At) g(this) g(point) h(thr) n(ead) f(A) g(is) -h(either) f(blocked) g(inside) p Fd 23 w(rea) n(d\(so) n(ck\)) p -Fg(,) g(or) g(is) h(elsewhe) n(r) n(e) g(in) 63 2570 -y(the) 18 b(loop.) 26 b(If) 18 b(the) g(former) h(then) f(r) n(ead) h -(will) h(r) n(eturn) e(0,) i(indicating) f(that) g(the) f(socke) n(t) h -(is) g(closed.) 26 b(If) 63 2683 y(the) 21 b(latter) h(then) f -(eventually) h(thr) n(ead) g(A) g(will) i(call) p Fd -24 w(rea) n(d\(so) n(ck\)) p Fg 21 w(and) f(then) e(this) h(will) h(r) n -(eturn) 63 2796 y(0.) 28 b(Thr) n(ead) 22 b(A) h(should) p -Fd 21 w(clos) n(e\(soc) n(k\)) p Fg(,) f(do) g(any) g(other) g(tidying) -f(up,) h(and) h(exit.) 204 2919 y(If) 34 b(ther) n(e) g(is) h(another) f -(point) g(in) h(the) e(loop) i(that) f(thr) n(ead) g(A) h(can) g(block) -g(then) f(obviously) 63 3032 y(thr) n(ead) 19 b(B) h(needs) f(to) h(be) -g(awar) n(e) h(of) f(this) g(and) g(be) h(able) g(to) e(wake) h(it) h -(up) f(in) g(the) g(appr) n(opriate) g(way) 63 3145 y(fr) n(om) j(that) -f(point.) p Fc 63 3462 a(6.2) 99 b(accept\(\)) p Fg 63 -3659 a(Again) 25 b(thr) n(ead) g(A) h(is) f(in) h(a) g(loop,) g(this) f -(time) h(doing) e(an) i(acc) r(ept) e(on) h(listenSock,) g(dealing) h -(with) 63 3772 y(a) d(new) f(connection) g(and) h(going) e(back) j -(into) e(accept.) 28 b(Thr) n(ead) 22 b(B) g(wants) h(to) f(cancel) h -(it.) 204 3895 y(On) g(Digital) h(Unix) f(3.2) g(the) f(strateg) n(y) g -(is) h(identical) h(to) e(that) g(for) h(r) n(ead:) 204 -4018 y(Thr) n(ead) 39 b(B) g(does) p Fd 38 w(shut) n(down) n(\(list) n -(enSo) n(ck,2) n(\)) p Fg(.) 79 b(Wher) n(ever) 38 b(thr) n(ead) h(A) h -(is) f(in) h(the) 63 4131 y(loop,) i(eventually) c(it) h(will) h(r) n -(eturn) p Fd 38 w(ECONN) n(ABOR) n(TED) p Fg 38 w(fr) n(om) f(the) f -(accept) h(call) r(.) 76 b(It) 39 b(shou) n(ld) p Fd -63 4244 a(clo) n(se\(l) n(isten) n(Sock) n(\)) p Fg(,) 22 -b(tidy) g(up) g(as) h(necessary) e(and) i(exit.) 204 -4367 y(On) 30 b(Solaris) f(2.5) i(thr) n(ead) e(B) g(can't) h(do) p -Fd 29 w(shu) n(tdow) n(n\(lis) n(tenS) n(ock,2) n(\)) p -Fg 29 w(\227) g(this) f(r) n(eturns) p Fd 63 4480 a(ENO) n(TCON) n(N) p -Fg(.) 22 b(Instead) f(the) h(following) h(strateg) n(y) g(can) g(be) g -(used) n(:) 204 4603 y(First) 35 b(thr) n(ead) h(B) g(set) n(s) g(some) -f(sort) g(of) h("shutdo) n(wn) g(\003ag") g(associated) g(with) g -(listenSock.) 63 4716 y(Then) 31 b(it) h(does) p Fd 30 -w(gets) n(ocka) n(ddr\(l) n(iste) n(nSock) n(\)) p Fg -32 w(to) f(\002nd) g(out) g(which) i(port) e(listenSock) f(is) 63 -4828 y(on) 18 b(\(or) h(knows) e(alr) n(eady\),) j(sets) d(up) h(a) h -(socket) e(dummySock,) i(doe) n(s) p Fd 19 w(con) n(nect) n(\(dumm) n -(ySoc) n(k,) 63 4941 y(thi) n(s) 54 b(host,) f(por) n(t\)) p -Fg 22 w(and) 23 b(\002nally) g(does) p Fd 21 w(clos) n(e\(dum) n(mySo) n -(ck\)) p Fg(.) 204 5064 y(Wher) n(ever) 16 b(thr) n(ead) h(A) g(is) g -(in) h(the) e(loop,) h(eventually) g(it) h(will) g(call) p -Fd 19 w(acce) n(pt\(li) n(sten) n(Sock) n(\)) p Fg(.) 63 -5177 y(This) 35 b(will) j(r) n(eturn) d(successfully) g(with) h(a) h -(new) e(socket,) j(say) e(connSock.) 67 b(Thr) n(ead) 36 -b(A) f(then) 63 5290 y(checks) 20 b(to) h(see) f(if) i(the) f("shutd) n -(own) g(\003ag") h(is) f(set.) 26 b(If) c(not,) e(then) h(it's) g(a) h -(normal) g(connection.) 27 b(If) 21 b(it) 63 5403 y(is) h(set,) g(then) -f(thr) n(ead) h(A) h(closes) f(listenSock) f(and) i(connSock,) e -(tidies) h(up) g(and) h(exits.) p 90 rotate dyy eop -%%Page: 6 6 -6 5 bop Fg 221 249 a(6) p Fe 1367 w(6) 91 b(THRE) n(ADED) 23 -b(I/O) g(SHUTDOWN) f(FOR) g(UNIX) p Fc 221 548 a(6.3) 99 -b(write\(\)) p Fg 221 768 a(Thr) n(ead) 19 b(A) f(may) h(be) g(blocked) -f(in) i(write,) f(or) f(about) h(to) f(go) g(in) h(to) g(a) g(poten) n -(tiall) r(y-blocking) g(write.) 221 881 y(Thr) n(ead) j(B) h(wants) f -(to) g(shut) f(it) i(down.) 362 1016 y(On) g(Solaris) g(2.5:) 362 -1150 y(Thr) n(ead) f(B) h(doe) n(s) p Fd 23 w(shu) n(tdown) n(\(soc) n -(k,2\)) p Fg -2 w(.) 362 1285 y(If) c(thr) n(ead) f(A) h(is) g(alr) n -(eady) g(in) p Fd 20 w(wri) n(te\(s) n(ock\)) p Fg 17 -w(then) f(it) h(will) i(r) n(eturn) d(with) p Fd 18 w(ENXIO) p -Fg -2 w(.) h(If) g(thr) n(ead) 221 1398 y(A) k(calls) h(write) e(after) -g(thr) n(ead) g(B) h(calls) h(shut) n(down) e(this) g(will) i(r) n -(eturn) p Fd 22 w(EIO) p Fg(.) 362 1532 y(On) f(Digital) h(Unix) f -(3.2:) 362 1666 y(Thr) n(ead) f(B) h(doe) n(s) p Fd 23 -w(shu) n(tdown) n(\(soc) n(k,2\)) p Fg -2 w(.) 362 1801 -y(If) h(thr) n(ead) f(A) g(is) h(alr) n(eady) g(in) p -Fd 24 w(writ) n(e\(so) n(ck\)) p Fg 23 w(then) e(it) i(will) h(r) n -(eturn) e(the) f(number) i(of) f(bytes) 221 1914 y(written) 31 -b(befor) n(e) h(it) g(became) g(blocked.) 55 b(A) 32 -b(subseq) n(uent) f(cal) r(l) h(to) f(write) h(will) h(then) e(gene) n -(rate) p Fd 221 2027 a(SIGP) n(IPE) p Fg 22 w(\(or) p -Fd 22 w(EPIP) n(E) p Fg 23 w(will) 24 b(be) e(r) n(eturned) f(if) p -Fd 24 w(SIG) n(PIPE) p Fg 21 w(is) i(ignor) n(ed) e(by) i(the) f(thr) n -(ead\).) p Fc 221 2413 a(6.4) 99 b(connect\(\)) p Fg -221 2634 a(Thr) n(ead) 30 b(A) f(may) h(be) g(blocked) f(in) i -(connect,) g(or) e(about) h(to) f(go) g(in) i(to) e(a) h(poten) n -(tiall) r(y-blocking) 221 2747 y(connect.) d(Thr) n(ead) c(B) f(wants) g -(to) g(shut) g(it) g(down.) 362 2881 y(On) h(Digital) h(Unix) f(3.2:) -362 3016 y(Thr) n(ead) f(B) h(doe) n(s) p Fd 23 w(shu) n(tdown) n -(\(soc) n(k,2\)) p Fg -2 w(.) 362 3150 y(If) j(thr) n(ead) f(A) g(is) h -(alr) n(eady) g(in) p Fd 26 w(conn) n(ect\() n(sock) n(\)) p -Fg 26 w(then) e(it) i(will) h(r) n(eturn) e(a) h(successful) f(con-) 221 -3263 y(nection.) 54 b(Subsequ) n(ent) 31 b(r) n(eading) g(or) g -(writing) g(will) i(show) d(that) i(the) e(socket) g(has) h(been) g -(shut) 221 3376 y(down) 22 b(\(i.e.) 28 b(r) n(ead) 23 -b(r) n(eturns) e(0,) i(write) f(generate) n(s) p Fd 23 -w(SIG) n(PIPE) p Fg 21 w(or) g(r) n(eturns) p Fd 22 w(EPI) n(PE) p -Fg(\).) g(If) h(thr) n(ead) f(A) 221 3489 y(call) r(s) g(connect) g -(after) h(thr) n(ead) f(B) g(call) r(s) g(shutdo) n(wn) h(this) f(will) -i(r) n(eturn) p Fd 22 w(EIN) n(VAL) p Fg(.) 362 3623 -y(On) f(Solaris) g(2.5:) 362 3758 y(Ther) n(e) 35 b(is) h(no) f(way) g -(to) g(wake) g(up) g(a) h(thr) n(ead) f(which) h(is) g(blocked) f(in) h -(connect.) 66 b(Inst) n(ead) 221 3871 y(Solaris) 33 b(for) n(ces) g(us) -f(thr) n(ough) g(a) i(ridiculous) f(pr) n(oced) n(ur) n(e) g(whichever) -g(way) g(we) f(try) g(it.) 59 b(One) 221 3984 y(way) 23 -b(is) f(this:) 362 4118 y(First) d(thr) n(ead) h(A) g(cr) n(eates) f(a) -h(pipe) g(in) g(addition) g(to) f(the) g(socket) n(.) 27 -b(Instead) 19 b(of) h(shut) n(ting) g(down) 221 4231 -y(the) i(socket) n(,) h(thr) n(ead) f(B) g(simply) h(writes) e(a) i -(byte) f(to) g(the) g(pipe.) 362 4365 y(Thr) n(ead) 17 -b(A) g(meanwhile) h(set) n(s) f(the) g(socke) n(t) g(to) g -(non-blocking) g(mode) f(using) p Fd 17 w(fcn) n(tl\(s) n(ock,) 221 -4478 y(F_SE) n(TFL,) 53 b(O_NO) n(NBLO) n(CK\)) p Fg(.) 26 -b(Then) h(it) g(cal) r(ls) g(connect) g(on) g(the) f(socket) g(\227) h -(this) g(will) i(r) n(eturn) p Fd 221 4591 a(EINP) n(ROGRE) n(SS) p -Fg(.) k(Then) h(it) h(must) e(cal) r(l) p Fd 35 w(sel) n(ect\() n(\)) p -Fg(,) k(waiting) e(for) f(either) g(sock) g(to) f(become) 221 -4704 y(writable) 39 b(or) f(for) h(the) e(pipe) h(to) g(become) g(r) n -(eadable.) 75 b(If) 39 b(select) e(r) n(eturns) g(that) i(just) e(sock) -h(is) 221 4817 y(writable) 30 b(then) f(the) g(connection) g(has) h -(succeede) n(d.) 49 b(It) 29 b(then) g(need) n(s) h(to) f(set) f(the) h -(socket) f(back) 221 4930 y(to) i(blocking) h(mode) f(using) p -Fd 30 w(fcnt) n(l\(so) n(ck,) 54 b(F_S) n(ETFL) n(,) h(0\)) p -Fg(.) c(If) 31 b(instead) e(select) h(r) n(eturns) 221 -5043 y(that) 23 b(the) e(pipe) h(is) h(r) n(eadable,) g(thr) n(ead) f -(A) h(closes) e(the) h(socket) n(,) h(tidies) f(up) g(and) h(exits.) 362 -5177 y(An) g(alternative) h(method) e(is) i(similar) h(but) e(to) g -(use) f(polling) i(instead) e(of) i(the) e(pipe.) 29 -b(Thr) n(ead) 221 5290 y(B) 24 b(justs) e(sets) g(a) j(\003ag) f(and) g -(thr) n(ead) f(A) h(calls) h(select) e(with) g(a) i(timeout,) e(period) -n(ica) r(lly) h(waking) f(up) 221 5403 y(to) f(see) g(if) h(the) f -(\003ag) h(has) f(been) g(set.) p 90 rotate dyy eop -%%Page: 7 7 -7 6 bop Fe 63 249 a(REF) n(ERENCES) p Fg 2660 w(7) p -Fh 63 548 a(Refere) n(nces) p Fg 63 759 a([POSIX94]) p -Fa 46 w(Portable) 29 b(Operat) r(ing) f(System) g(Interface) h -(\(POSIX\)) e(Thr) n(ea) r(ds) h(Extension) p Fg(,) h(P1003) r(.1c) 245 -872 y(Draft) 23 b(10,) g(IEEE,) e(Septe) n(mber) i(1994) r(.) 63 -1059 y([Birr) n(ell89]) p Fa 47 w(An) 28 b(Intr) n(od) r(uction) g(to) h -(Pr) n(ogr) r(amming) g(with) g(Thr) n(ead) r(s) p Fg(,) h(Rese) n(ar) n -(ch) g(Repo) n(rt) e(35,) j(DEC) 245 1172 y(Syst) n(ems) 22 -b(Resear) n(ch) g(Center) -7 b(,) 22 b(Palo) h(Alto,) f(CA,) h(January) -g(1989) r(.) p 90 rotate dyy eop -%%Trailer -end -userdict /end-hook known{end-hook}if -%%EOF |