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Reference Guide
 
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Format of the root (first) directory record

Format of the root (first) directory record in release 6.22.06. It is never compressed.

This directory record differs from subdirectories (see Format of a TDirectory record) in the additional Name and Title at the beginning of the DATA (after the TKey).

If the SeekKeys or SeekPdir in the TKey are located past the 32 bit file limit (> 2000000000), then these fields will be 8 instead of 4 bytes and 1000 is added to the TKey Version.

If the SeekDir, SeekParent, or SeekKeys in the TDirectory header are past the 32 bit file limit, then these fields will be 8 instead of 4 bytes and 1000 is added to the TDirectory Version.

-------—TKey------------—

Byte Range Member Name Description
0...3 Nbytes Number of bytes compressed record (TKey+data) TKey::fNbytes
4...5 Version TKey class version identifier TKey::fVersion
6...9 ObjLen Number of bytes of uncompressed data TKey::fObjLen
10...13 Datime Date and time when record was written to file TKey::fDatime (year-1995)<<26&#124;month<<22&#124;day<<17&#124;hour<<12&#124;minute<<6&#124;second
14...15 KeyLen Number of bytes in key structure (TKey) TKey::fKeyLen
16...17 Cycle Cycle of key TKey::fCycle
18...21 [18...25] SeekKey Byte offset of record itself (consistency check) (64) TKey::fSeekKey
22...25 [26...33] SeekPdir Byte offset of parent directory record (0) TKey::fSeekPdir
26...26 [34...34] lname Number of bytes in the class name (5) TKey::fClassName
27..... [35...] ClassName Object Class Name ("TFile") TKey::fClassName
0...0 lname Number of bytes in the object name TNamed::fName
1... Name lName bytes with the name of the object <file-name> TNamed::fName
0...0 lTitle Number of bytes in the object title TNamed::fTitle
1... Title lTitle bytes with the title of the object <file-title> TNamed::fTitle

-----—DATA--------------—

Byte Range Member Name Description
0...0 lname Number of bytes in the TFile name TNamed::fName
1... Name lName bytes with the name of the TFile <file-name> TNamed::fName
0...0 lTitle Number of bytes in the TFile title TNamed::fTitle
1... Title lTitle bytes with the title of the TFile <file-title> TNamed::fTitle
0...1 Version TDirectory class version identifier TDirectory::Class_Version()
2...5 DatimeC Date and time when directory was created TDirectory::fDatimeC (year-1995)<<26&#124;month<<22&#124;day<<17&#124;hour<<12&#124;minute<<6&#124;second
6...9 DatimeM Date and time when directory was last modified TDirectory::fDatimeM (year-1995)<<26&#124;month<<22&#124;day<<17&#124;hour<<12&#124;minute<<6&#124;second
10...13 NbytesKeys Number of bytes in the associated KeysList record TDirectory::fNbyteskeys
14...17 NbytesName Number of bytes in TKey+TNamed at creation TDirectory::fNbytesName
18...21 [18...25] SeekDir Byte offset of directory record in file (64) TDirectory::fSeekDir
22...25 [26...33] SeekParent Byte offset of parent directory record in file (0) TDirectory::fSeekParent
26...29 [34...41] SeekKeys Byte offset of associated KeysList record in file TDirectory::fSeekKeys