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--- root:troubleshooting [2010/11/09 16:02] – nchiap
+++ root:troubleshooting [2013/06/14 12:11] – nchiap
@@ Line 1: / Line 1: @@
-====== Writing Root-files ======
+====== Root-files ======
-<code C>
-TFile* inputFile = TFile::Open("myInputFile.root");
+Root-files can be the source of various problems.
-TFile* outputFile = new TFile("myOutputFile.root", "RECREATE");
+Usually they are caused by hidden changes in the internal state of ROOT.
-// your code
+ROOT stores the active directory.
-outputFile->Write();
+When a new histograms is created,  in the active directoy, existing histograms are looked for in
-</code>
 ===== Empty Files =====
@@ Line 14: / Line 13: @@
 TFile* outputFile = new TFile("myOutputFile.root", "RECREATE");
 TFile* inputFile = TFile::Open("myInputFile.root");
+// your code
+outputFile->Write();
+</code>
+but instead do:
+<code C>
+TFile* inputFile = TFile::Open("myInputFile.root");
+TFile* outputFile = new TFile("myOutputFile.root", "RECREATE");
 // your code
 outputFile->Write();
 </code>

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