Re: some confusion about TString

Rene Brun (Rene.Brun@cern.ch)
Wed, 10 Mar 1999 11:03:56 +0000

Petar Maksimovic wrote:
>
> Hi all,
>
> I'm a little confused about some uses of the TString class. What I
> ultimately want to do is to tokenize a command line. (I'm trying to
> write a layer on top of TMinuit::mnexcm() and avoid creating the
> annoying array of needed to supply arguments.)
>
> The web page for TString claims that there is a member function
> istream& ReadToken(istream& str) that seems perfect for the job. Does
> anybody have an example on how to use it (the whole root web site
> contains only two references to it -- in the class definition).
>
> Also, one would naively expect the following few commands to work:
>
> root [0] #include <iostream.h>
> root [1] TString test = "one two three";
> root [2] cout << test << endl;
>
> *** Break *** segmentation violation
>
> I'd appreciate a hint on what I'm missing here.
>
> I'm using root 2.21/02. Thanks a bunch!
>
> Petar

Hi Petar,
In Root 2.21/03, Fons fixed a problem in Tstring::ReadToken.
At least, I checked that your above commands work correctly with
our current version 2.21/07.

Note that TMinuit has a member function TMinuit::mncomd to execute
a const char *command. There were several problems with this function.
They were fixed in 2.21/05

Christian lacunza has suggested a set of new functions in the TMinuit
class.
These functions simplify the use of the TMinuit class:
I have added TMinuit::Command(const char *command) also.

Int_t Command(const char *command);
Int_t DefineParameter( Int_t parNo, const char *name, Double_t
initVal, Double_t initErr, Double_t lowerLimit, Double_t
upperLimit );
Int_t FixParameter( Int_t parNo );
Int_t GetParameter( Int_t parNo, Double_t& current_value,
Double_t& current_error );
Int_t Migrad();
Int_t Release( Int_t parNo );
Int_t SetErrorDef( Double_t up );
Int_t SetPrintLevel( Int_t printLevel=0 );

Rene Brun