= How do i begin playing with CMT ? =

by V.Garonne     [[BR]]
Date: 05.4.2005  [[BR]]
Version : 0.1    [[BR]]


== A package creation: The classic Hello world example ==

We do here the classic "Hello World" example with CMT. 
First we create the cmt package called "test" with version 1:

{{{
> cmt create test v1
------------------------------------------
Configuring environment for package test version v1.
CMT version v1r18p20050501.
Root set to /users/dsksi/garonne.
System is Linux-i686
------------------------------------------
Installing the package directory
Installing the version directory
Installing the cmt directory
Installing the src directory
Creating setup scripts.
Creating cleanup scripts.
> cd test/v1
> ls 
cmt src
}}}
We see here that a directory tree has been created. We now create and writte our small "C++" program (main.cxx, hello.h and hello.cxx).[[BR]] We have:
{{{
> more src/hello.h
//////////////////////////////////////////////////
// author: vincent garonne                      //
// date:   4/5/2005                             //
// description: hello world description file    //
//////////////////////////////////////////////////

#ifndef __HELLO_WORLD__
#define __HELLO_WORLD__

class hello
{
    public:
        // constructor
        hello  () {}
        
        // desctructor
        ~hello (){}

        // function example
        void print ();
};
#endif // __HELLO_WORLD__
> more src/hello.cxx
//////////////////////////////////////////////////
// author: vincent garonne                      //
// date:   4/5/2005                             //
// description: hello world body                //
//////////////////////////////////////////////////

using namespace std;
#include <iostream>

#include "hello.h"

void hello::print ()
{
        cout<<"Hello le world !!!"<<endl;
}
> more src/main.cxx
//////////////////////////////////////////////////
// author: vincent garonne                      //
// date:   4/5/2005                             //
// description: main program                    //
//////////////////////////////////////////////////
#include "hello.h"

int main ()
{     
     hello object;
     object.print();
     return 0;
}
}}}

Then to construct the executable, we need to specify within the "requirements" file in the cmt directory :
{{{
> cd cmt
> more requirements
package       test
author        Vincent Garonne <garonne@lal.in2p3.fr>
application   test hello.cxx main.cxx
}}}
Now we can compil and execute:
{{{
> cmt make
...
> source setup.csh
> ../Linux-i686/test.exe
Hello le world !!!
}}}

By default the executable has been put in the Linux-i687 directory.

== The library creation ==

To create the hello library, it need to specify one more line in the requirements file.
{{{
> more requirements
package       test
author        Vincent Garonne <garonne@lal.in2p3.fr>
application   test hello.cxx main.cxx
library       hello hello.cxx
> cmt make
...
> ls ../Linux-i686/libhello.*
../Linux-i686/libhello.a  ../Linux-i686/libhello.so
}}}

The libraries have been built.