Wefts++ is an high-level abstraction C++ threading library, which has also seamless integration with low level constructs when raw speed is needed.
Wefts++ does not pretends to be a bleeding edge research library; what Wefts++ wants to be is just a set of utility objects making multithreading with C++ easier, that will lay gracefully on your C++ application design.
Wefts++ amis to help you develop C++ multithreading application easily and swiftly. Thread programming is an art, and wefts is your paintbrush
Wefts++ library can be obtained in form of tar gzipped sources, in form of RPM source package or pre-compiled RPM binaries. Installation is easy and it will just install a set of headers and a couple of very small libraries.
It is also possible to get latest development status of Wefts by downloading the CVS archive:
cvs -z9 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/wefts login Password: <press enter here> cvs -z9 -d:pserver:anonymous@cvs.sourceforge.net:/cvsroot/wefts co wefts
Under GNU compliant systems, (and also under a lot of unices) a
./configure make make install (** read note)
should be enough. Wefts are installed by default into /usr/local/lib/wefts. That directory will contain an include/ subdirectory, where all the include files are added and lib/ subdirectory, where you can found static (and if you care to build them, dynamic) libraries.
You can change this default with the option:
./configure --prefix=/my/favorite/
You could i.e. install wefts libs under /usr/libs and include files under /usr/include by just configuring with --prefix=/usr (if you find this library really useful :-). You could also set specific destination for wefts headers and libraries. In example:
./configure --prefix=/usr --libdir=lib/wefts --includedir=include/wefts
will move libraries and includes in your system standard directory, but under wefts subdirectory (/usr/include/wefts for headers and /usr/lib/wefts for libraries).
Provided you have autoconf 2.5+, automake 1.6+ and a recent libtool, this command sequence should be enough:
aclocal libtoolize --automake autoconf autoheader automake -a
And then you can continue with configure, make and make install. "automake -a" is important, as it will create the standard GNU support utilities to do a clean configure/make process.
To enable debugging symbols add --enable-debug, and to make also tests (linked against static library) do --enable-tests.
Dynamic libraries can be built by passing --enabled-shared to configure. Anyhow, wefts is a very small library, and most of it is held in inline C++ methods; for this reason, using only the static library version makes perfectly sense.
Wefts can also be installed from RPM on Mandrake and Red Hat LINUX systems, and on those systems that support RPM. The library installation is done under /usr/lib, include files are installed in /usr/include/wefts, while wefts-conf script is placed in /usr/bin dir.
To install the package, you need libpthread.a to be in /usr/lib.
The command rpm -ivh wefts-...rpm will be enough.
Once you have configured and installed the package, if you don't like the libraries anymore ;,( a make uninstall will remove installed files.
If you have installed using rpm, the command rpm -e wefts will remove the package.
This manual is meant to be just an api reference (and a configuration guide) for Wefts; cute tutorials, FAQ, and other things like that can be found at wefts home site http://wefts.sourceforge.net.
However, we present here a minimal survival guide on how to compile and use wefts.
To test if your installation is correct, check out this test:
// $Id: weftstest.cpp,v 1.1 2003/08/16 20:45:57 jonnymind Exp $ // weftstest.cpp - an introductory test // // This program is free software - GPL 2.0 license // (C) Giancarlo Niccolai // // NOTE: this program is demonstrative and hence not compiled // in the make process of Wefts test suite. // #include <wefts.h> #include <iostream> using namespace Wefts; using namespace std; class MyThread: public Thread { void *run() { cout << "Begin of thread" << sequence() -1 << endl; Sleep( 2.5 ); cout << "End of thread" << sequence() -1 << endl; return 0; } }; int main( int argc, char *argv[] ) { for ( int i = 0;i < 4; i ++ ) { MyThread *th = new MyThread(); th->start(); } //we'll wait for our children to terminate: runningThreads.until( 1 ); // until there is only 1 thread left (myself). cout << "Main thread done!" << endl; return 0; }
This simple program can be compiled using the command
$ gcc -o weftstest $(wefts-conf -c) weftstest.cpp $(wefts-conf -s -l)
This command will call wefts-conf two times; the first one will provide some basic C++ flag, including the "include" dir that is needed to do include <wefts.h>. The second one will tell where to get the wefts library that has to be linked.
If you don't have installed dynamic libraries, (that is, if you don't have enabled them with --enable-shared in configure script), that "-s" option in wefts-conf isn't necessary. In fact, that option just tells to get exactly the static library. Wefts is a very small library (under 50 Kb), so it is possible that the final developer does not want to link against dynamic libraries, with the need to install them everywhere the program has to run.
Dynamic libraries are a little more tricker. By default they are installed in /usr/local/lib/wefts/lib; this means that you need to do something to tell the program loader where the libraries are, to use them. You can do three ways:
gian@head$ gcc -o weftstest $(wefts-conf -c) weftstest.cpp $(wefts-conf -l)
gian@head$ ./weftstest
./weftstest: error while loading shared libraries: libwefts.so.1: cannot open shared object file: No such file or directory
gian@head$ LD_LIBRARY_PATH=$(wefts-conf -p) ./weftstest
Begin of thread1
...
...
Main thread done!
gian@head$
Ok, Ok, I feel that way too :-)
So, what can you do now? The main class here is Wefts::Thread; have a look at it. Then you will need some way to synchronize threads: Wefts::Mutex and Wefts::RMutex are what you are searching for.
If you are accustomed with posix condition and signals, the Wefts::Condition, Wefts::FastCondition and Wefts::RCondition classes are implementing that model. If you are not accustomed with them, or if you have enough of condition signaling, well, have a look at them anyway; you could find new way to use them in this C++ object oriented environment. They are absolutely excellent to send safely a data that is produced in a thread to another thread that is waiting for that. (If you use them directly, and if you plan to use thread cancellation, be sure to read Condition cleanup)
A little step further is required for Wefts::XMutex, Wefts::RWMutex and Wefts::RRWMutex.
Then, when you have a certain mastery with this classes, have a look at the Wefts::Barrier, Wefts::RingBuffer, the Wefts::Subscription and finally the Wefts::MoaningThread (TM). -- this (TM) is a joke.
Almost all features are demonstrated by little programs in the tests/ subdirectory of the source distribution (both SRPM and tarball has it, or you can browse our CVS). They will be compiled (from tarball) if you set ./configure --enable-tests.
They are somehow self explanatory, and are worth a look anyway.
Each one is meant to do some MESSY test with the library thing. You are supposed to read the header that is displayed at program begin; if it goes away too fast, it is because you are supposed to read it by scrolling back and then see the results of the experiments with caml, after the program is finished; you may also want to to dump the results by redirecting them to a file. In the test sources there are LOTS of comments explaining why certain things are done in certain ways; if you want to learn Wefting, that is a fairly good point to start.
Sorry. Not here. Try to see http://wefts.sf.net to see if me (or another contributor) had the time to add some. Or scan the net to see how other programmers have solved the problem you have. And if you are lost, send me a mail. (My address is about everywhere in the distribution...)
But ... to be honest in release 0.9 there is a fairly good section explaining how to use basic conditions and mutexes; big issues (like the most powerful objects) are left out, but you may want to check Some example.
Enjoy Wefting!
Giancarlo Niccolai
1.2.18