Using STL vectors of non-basic type

ROOT
1

Dear all,
I came across the following.
Define a user class:

#include <iostream>
class myclass
{
public:
  Int_t x[100];
  Int_t y[100];
  inline myclass() { }
  virtual inline ~myclass() {  }
  ClassDef(myclass,1)
    };

and then execute

so that myclass gets compiled and added to the list of classes which can be used interactively. However, if I try to make an STL vector from this class:

vector <myclass> x; x.resize(10);
then the system will crash, displaying messages like “Shared object disappeared from memory”, etc.
Is this because STL vectors of non-basic type cannot be used in the interactive sesions (only in compiled programs) ? I have written several classes which read and write trees with classes which encapsulate STL vectors of my own classes and didn’t have any trouble untill I tried to access the vectors interactively to get out some numeric values. It seems that in order to display the values stored, each time I have to write corresponding methods in my (g++ compiled) analysis classes … I made sure that I’m including and using namespace std. If I try

vector <Int_t> a;
a.resize(10);
a[0] = 0;
a[0] <ENTER> 
(int)0

in an interactive Root-session, then there is no problems. What am I doing wrong?
Thank you,
Dmitri.

2

I have tried to use a _linkdef.h - file with the following:

#pragma link C++ class myclass; #pragma link C++ class std::vector<myclass> and now this seems to be working. Is this the only thing that I was missing in the above code? Or should I expect more surprises (unexpected memory leaks) once I start processing large STL vectors?

3

Hi Dmitri,
the dictionary for your STL collection is all you need. There are large amounts of data written with STL collections, so you should be fine.
Cheers, Axel.

4

I’m trying to do something even simpler: use a vector.

I have the following pragma.C:

#include <vector> #ifdef __MAKECINT__ #pragma link C++ class vector<unsigned int>+; #endif

and when I do .L pragma.C+ and declare a vector I get

[quote]root [0] .L pragma.C+
Info in TUnixSystem::ACLiC: creating shared library /home/rsholmes/Compton/compton/acpa/./pragma_C.so
Note: Link requested for already precompiled class vector<unsigned int,allocator > (ignore this message) :0:
root [1] vector test
Error: vector<unsigned int,allocator >() no default constructor (tmpfile):1:
*** Interpreter error recovered ***
[/quote]

If I pay attention to the message it says to ignore, and postulate that there already is a dictionary for vector, this happens:

[quote]root [0] vector test
root [1] test.push_back(3)
Error: Can’t call vector<unsigned int,allocator >::push_back(3) in current scope (tmpfile):1:
Possible candidates are…
(in vector<unsigned int,allocator >)
*** Interpreter error recovered ***
[/quote]

What am I missing? (I’m using ROOT 5.17/02).

5

Hi,

For simple type, ROOT provide the dictionary (in what is a called a cint dlls).
To load it, simply do:

I.e. have the interpreter execute the #include

Note that in ROOT 5.19/04, this has been automated (i.e. typing vector willl autoload the cintdlls).

Cheers,
Philippe.