TTree and STL vector

ROOT
#1

Hi,

I try to get TTree* working with STL vector in CINT. Here is the relevant part of my code (ROOT 5.10-00):

std::vector fTrees;
fTrees.push_back( (TTree*) fFile->Get(“MuPlus”) ); // fFile is of type TFile*
fTrees.push_back( (TTree*) fFile->Get(“MuMinus”) ); // MuPlus and MuMinus
// are valid tree names
int curEvtID;
for ( std::vector::iterator treeItr = fTrees.begin();
treeItr != fTrees.end(); treeItr++ ) {
treeItr->SetBranchAddress(“EventID”, &curEvtID);
}

CINT stops at treeItr->SetBranchAddress(“EventID”, &curEvtID) with the error: “non class,struct,union object treeItr used with . or ->”.

Using either “(*treeIt)->” or “&(*treeItr)->” leads to a segmentation fault.

Anybody any idea what’s wrong here?

Cheers, Alexander

#2

You have an error in the definition of your std::vector. Instead of

it should be

Rene

#3

Dummy

#4

Sorry, this is a typo in the posted text. I do have

in my code. Also the correct loop line in my code reads

Alexander

#5

[quote]CINT stops at treeItr->SetBranchAddress(“EventID”, &curEvtID) with the error: “non class,struct,union object treeItr used with . or ->”. [/quote]This actually accurate since the type of ‘treeItr->’ is TTree* and hence you still need to dereference it.

In simple tries I got:

root [8] (*treeItr)->GetName() (const char* 0x14048f8)"T1"

Now the possible problem is that the file has been closed (and hence the TTree object has been deleted and hence the pointers are invalid).

Cheers,
Philippe

#6

Hi Philippe,
thanks for the help but I don’t think it is the status of the file. I just tried the following

TTree* tree;
...
cout << tree->GetName() << endl;
std::vector<TTree*> fTrees;
fTrees.push_back(tree);
for ( std::vector<TTree*>::iterator treeItr = fTrees.begin(); 
       treeItr != fTrees.end(); treeItr++ ) {
  cout << (*treeItr)->GetName() << endl;
}

The first ‘cout’ line gives the correct answer where for the second I get a segmentation fault. So it cannot be the status of the file.

Actually, the whole thing works when I type it on the root command line. In my program fTrees is defined as a private variable in a class. The push_back is done in a method of this class. Could the class structure be the reason for the segmentation fault?

Cheers, Alexander

#7

Hi Alexander,

[quote] Could the class structure be the reason for the segmentation fault? [/quote]It is hard to tell. I recommend that you send me a complete running example so that I can reproduce your observations.

Cheers,
Philippe

#8

Hi Philippe,

I attached a compressed version of my program which shows the same “features” as the full version.

In the current form the program crashes at the ‘cout’ with a segmentation fault. However, after commenting out the ‘while’ loop in ‘Simulation::Process’ the program runs without a problem. Also, compiling the original version (including the ‘while’ loop) with .L test.C+ and running test() afterwards is ok.

I can’t imagine that the ‘while’ loop itself is the problem. But I don’t know what could be the real cause for the segmentation violation.

As a note: Actually, I would prefer to compile the program but the classes that I have to use need the ‘shared_ptr’ from the ‘boost’ package. Up to now I haven’t managed to integrate them in the correct way. Compiling the program in root yields a lot of error messages of the form

Error: no such template shared_ptr<...> FILENAME:LINENUMBER:

Any idea here would also be welcome.

Cheers, Alexander
test.C (1.02 KB)

#9

Unfortunately this is known problem of the CINT byte-code optimizer.

You have several work-arounds:
[ul]Disable the CINT optimizer by issuing the CINT command .O 0
Generate a dictionary for vector<TTree*> (see below)
Compile your code (use ACLiC for examepl)[/ul]

[quote] that I have to use need the ‘shared_ptr’ from the ‘boost’ package.
[/quote]

You need to hide all boost header file from CINT:#ifndef __CINT__ #include <boost/shared_ptr.h> #endif

You also may need to hide data member and function using it.

Cheers,
Philippe.

To generate a dictionary for vector<TTree*>, you simple need a file containing:#include <vector> class TTree; #ifdef __MAKECINT__ #pragma link C++ class vector<TTree*>; #pragma link C++ class vector<TTree*>::iterator; #pragma link C++ function operator==(const vector<TTree*>::iterator&,const vector<TTree*>::iterator&); #endif
and load it via ACLiC.

#10

[quote]To generate a dictionary for vector<TTree*>, you simple need a file containing:#include <vector> class TTree; #ifdef __MAKECINT__ #pragma link C++ class vector<TTree*>; #pragma link C++ class vector<TTree*>::iterator; #pragma link C++ function operator==(const vector<TTree*>::iterator&,const vector<TTree*>::iterator&); #endif
and load it via ACLiC.[/quote]

Great, it works now! Thanks a lot, Philippe!

I also will try to compile the program. You write

[quote] You need to hide all boost header file from CINT:

#ifndef __CINT__
#include <boost/shared_ptr.h>
#endif

You also may need to hide data member and function using it.[/quote]
I’m not familiar with the way programs are compiled with ACLiC so what exactly is happening? From what you write I understand that CINT is called first (what is it doing?) and has trouble with the shared_ptr. What happens afterwards?

Cheers, Alexander

#11

You can find the details about ACLiC in the User’s Guide :slight_smile:
In short ACLiC does
[ul] - run rootcint (and hence CINT) on your script to generate the dictionary for the symbol declared in your scripts (and its header file)

  • run the compiler to generate a shared library containing your script and its dictionary
  • load the resulting shared library.[/ul]

Cheers,
Philippe.