I've changed your macro (see below).
The corrections were that:
1. Each section with TFile declaration was enclosed in the {}.
It is bad that CINT doesn't print error message 'second declaration'
for the code
{
TFile file("test.root","recreate");
TFile file("test.root","update");
}
2. file->ls() is correct only if 'file' is declared as pointer:
TFile *file = new TFile(...)
Use file.ls() in the case of TFile file(...)
Unfortunately CINT doesn't print error message for the code
{
TFile file("test.root","recreate");
file->Close();
}
3. gDirectory->ls() was replaced by file.ls()
4. gDirectory->cd() was replaced by file.cd()
5. gDirectory->mkdir(...) was replaced by file.mkdir(...)
class TFile : public TDirectory
Read the pages:
http://root.cern.ch/root/html/TFile.html
http://root.cern.ch/root/html/TDirectory.html
Your macro:
{
{
gROOT.Reset();
TFile file("test.root","recreate");
file.mkdir("dir1");
file.cd("dir1");
named = new TNamed("amo","amo");
named->Write("amo");
file.ls();
file.Write();
file.Close();
printf("------file closed-------\n");
}
{
TFile file("test.root","update");
file.cd("dir1");
named = new TNamed("eva","eva");
named->Write("eva");
file.ls();
file.Write();
file.Close();
printf("------file closed-------\n");
}
{
TFile file("test.root","update");
file.ls();
file.cd("dir1");
file.ls();
}
}
With best wishes,
Alexander Yuryevich Zvyagin.
>Sorry for this question, but I checked tutorials and documentation
>without
>success. My problem: Once I closed a root file, im not able to write
>again
>into an already created directory. The newly written object appears
>in memory but not on disk. After closing and reopening the file it is
>lost.
>ALso I cant delete an object after reopening the file.
>So what is wrong with the following test macro??
>
>
>{
> gROOT.Reset();
> TFile file("test.root","recreate");
> gDirectory->mkdir("dir1");
> gDirectory->cd("dir1");
> named = new TNamed("amo","amo");
> named->Write("amo");
> gDirectory->ls();
> file->Write();
> file->Close();
> printf("------file closed-------\n");
>
> TFile file("test.root","update");
> gDirectory->cd("dir1");
> named = new TNamed("eva","eva");
> named->Write("eva");
> gDirectory->ls();
> file->Write();
> file->Close();
> printf("------file closed-------\n");
>
> TFile file("test.root","update");
> gDirectory->cd("dir1");
> gDirectory->ls();
>}
>
>and this is the output:
>
>root [0] .x new.C
>TDirectory* dir1 dir1
> KEY: TNamed amo;1 amo
>TFile Writing Name=test.root Title=
>------file closed-------
>TDirectory* dir1 dir1
> KEY: TNamed amo;1 amo
> KEY: TNamed eva;1 eva
>TFile Writing Name=test.root Title=
>------file closed-------
>TDirectory* dir1 dir1
> KEY: TNamed amo;1 amo
>root [1]
>--------------------------------------------------
>
>and eva is lost!
>Thanks in advance
> Hajo!
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