Re: Compiling a root macro like a c++ program

Hi Valeri!

On 10 Apr 2007, at 22:48, Fine, Valeri wrote:

> Hi ,
> replace the name of your subroutine from "main" to "test", remove
> the parameters, try again:
>
> #include <stdio.h>
> #include <stdlib.h>
> #include <iostream.h>
>
> int test()
> {
> cout<<"Hello World!"<<endl;
> return 0;
> }
>
>
> No application can contains TWO different subroutines with one and
> the same name , namely "main". ROOT itself is the "main"
> subroutine. You tried to load the second one.
>

Well, I just tried to link two object files containing a main() routine each and the linker told me:

/usr/bin/ld: multiple definitions of symbol _main types.o definition of _main in section (__TEXT,__text) cd.o definition of _main in section (__TEXT,__text) collect2: ld returned 1 exit status

So, this obviously cannot be John's problem. Also, none of the ROOT shared libraries provides a main() because that would break all kinds of stuff... Maybe your misunderstanding was that John tried to compile a standalone program, not a ROOT macro to be executed from within CINT (be it compiled or not).

> -----Original Message-----
> From: owner-roottalk_at_pcroot.cern.ch [mailto:owner-
> roottalk_at_pcroot.cern.ch] On Behalf Of John Zoidberg
> Sent: Tuesday, April 10, 2007 4:35 AM
> To: roottalk_at_root.cern.ch
> Subject: [ROOT] Compiling a root macro like a c++ program
>
> I would like to make programs using ROOT classes, but compiled with
> the gcc/g++ compilers instead of this weird ACLiC/CINT system.
> I tried to understand the Makefile of the "test" folder with all
> the example programs, but it looks completely obscure to me.
>
> So I just tried reusing the command lines used when running this
> makefile, to compile a simple "hello world" program containing no
> ROOT code a all for the moment:
>
>
> g++ -O -Wall -fPIC -pthread -I/misc/cbmsoft/Debian3.1/new/tools/
> root/include -c test.cxx
> g++ -O test.o /u/mtaverne/root_compilation/libEvent.so -L/misc/
> cbmsoft/Debian3.1/new/tools/root/lib -lCore -lCint -lHist -lGraf -
> lGraf3d -lGpad -lTree -lRint -lPostscript -lMatrix -lPhysics -
> pthread -lm -ldl -rdynamic -o test
>
> Here's the test.cxx file:
> #include <stdio.h>
> #include <stdlib.h>
> #include <iostream.h>
>
> int main(int argc, char **argv)
> {
> cout<<"Hello World!"<<endl;
> return(0);
> }
> (It includes more headers than needed, but that shouldn't be a
> problem.)
>
> What I don't understand is that it does get compiled, but when I
> execute it, it displays nothing (whereas it does when I compile it
> with a simple "g++ test.cxx").
>

Ciao,

                     Roland

--
TU Muenchen, Physik-Department E18, James-Franck-Str., 85748 Garching
Telefon 089/289-12575; Telefax 089/289-12570
--
CERN office: 892-1-D23 phone: +41 22 7676540 mobile: +41 76 487 4482
--
Any society that would give up a little liberty to gain a little
security will deserve neither and lose both.  - Benjamin Franklin
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GS/CS/M/MU d-(++) s:+ a-> C+++ UL++++ P+++ L+++ E(+) W+ !N K- w--- M 
+ !V Y+
PGP++ t+(++) 5 R+ tv-- b+ DI++ e+++>++++ h---- y+++
------END GEEK CODE BLOCK------










application/pkcs7-signature attachment: smime.p7s



application/pgp-signature attachment: This is a digitally signed message part