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ROOT 6.10/09 Reference Guide |
This class implements a shared memory region mapped to a file.
Objects can be placed into this shared memory area using the Add() member function. To actually place a copy of the object is shared memory call Update() also whenever the mapped object(s) change(s) call Update() to put a fresh copy in the shared memory. This extra step is necessary since it is not possible to share objects with virtual pointers between processes (the vtbl ptr points to the originators unique address space and can not be used by the consumer process(es)). Consumer processes can map the memory region from this file and access the objects stored in it via the Get() method (which returns a copy of the object stored in the shared memory with correct vtbl ptr set). Only objects of classes with a Streamer() member function defined can be shared.
I know the current implementation is not ideal (you need to copy to and from the shared memory file) but the main problem is with the class' virtual_table pointer. This pointer points to a table unique for every process. Therefore, different options are:
Option 1) saves one copy, but requires solid copy ctor's (along the full inheritance chain) to rebuild the object in the consumer. Most classes don't provide these copy ctor's, especially not when objects contain collections, etc. 2) is too limiting or dangerous (calling accidentally a virtual function will segv). So since we have a robust Streamer mechanism I opted for 3).
Definition at line 26 of file TMapFile.h.
Public Types | |
enum | { kDefaultMapSize = 0x80000 } |
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enum | { kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff } |
enum | { kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) } |
enum | EStatusBits { kCanDelete = BIT(0), kMustCleanup = BIT(3), kObjInCanvas = BIT(3), kIsReferenced = BIT(4), kHasUUID = BIT(5), kCannotPick = BIT(6), kNoContextMenu = BIT(8), kInvalidObject = BIT(13) } |
Public Member Functions | |
virtual | ~TMapFile () |
TMapFiles may not be deleted, since we want to keep the complete TMapFile object in the mapped file for later re-use. More... | |
void | Add (const TObject *obj, const char *name="") |
Add an object to the list of objects to be stored in shared memory. More... | |
void | Browse (TBrowser *b) |
Browse contents of TMapFile. More... | |
Bool_t | cd (const char *path=0) |
Cd to associated directory. More... | |
void | Close (Option_t *option="") |
Close a mapped file. More... | |
TObject * | Get (const char *name, TObject *retObj=0) |
Return pointer to object retrieved from shared memory. More... | |
void * | GetBaseAddr () const |
void * | GetBreakval () const |
Return the current location in the memory region for this malloc heap which represents the end of memory in use. More... | |
TDirectory * | GetDirectory () const |
Int_t | GetFd () const |
TMapRec * | GetFirst () const |
TMapRec * | GetLast () const |
void * | GetMmallocDesc () const |
const char * | GetName () const |
Returns name of object. More... | |
const char * | GetOption () const |
Int_t | GetSize () const |
const char * | GetTitle () const |
Returns title of object. More... | |
Bool_t | IsFolder () const |
Returns kTRUE in case object is a folder (i.e. contains browsable lists). More... | |
Bool_t | IsWritable () const |
void | ls (Option_t *option="") const |
List contents of TMapFile. More... | |
void | operator delete (void *vp) |
Need special "operator delete" in which we close the shared memory. More... | |
void * | OrgAddress (void *addr) const |
void | Print (Option_t *option="") const |
Print some info about the mapped file. More... | |
TObject * | Remove (TObject *obj) |
TObject * | Remove (const char *name) |
void | RemoveAll () |
Remove all objects from shared memory. More... | |
void | Update (TObject *obj=0) |
Update an object (or all objects, if obj == 0) in shared memory. More... | |
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TObject () | |
TObject constructor. More... | |
TObject (const TObject &object) | |
TObject copy ctor. More... | |
virtual | ~TObject () |
TObject destructor. More... | |
void | AbstractMethod (const char *method) const |
Use this method to implement an "abstract" method that you don't want to leave purely abstract. More... | |
virtual void | AppendPad (Option_t *option="") |
Append graphics object to current pad. More... | |
virtual const char * | ClassName () const |
Returns name of class to which the object belongs. More... | |
virtual void | Clear (Option_t *="") |
virtual TObject * | Clone (const char *newname="") const |
Make a clone of an object using the Streamer facility. More... | |
virtual Int_t | Compare (const TObject *obj) const |
Compare abstract method. More... | |
virtual void | Copy (TObject &object) const |
Copy this to obj. More... | |
virtual void | Delete (Option_t *option="") |
Delete this object. More... | |
virtual Int_t | DistancetoPrimitive (Int_t px, Int_t py) |
Computes distance from point (px,py) to the object. More... | |
virtual void | Draw (Option_t *option="") |
Default Draw method for all objects. More... | |
virtual void | DrawClass () const |
Draw class inheritance tree of the class to which this object belongs. More... | |
virtual TObject * | DrawClone (Option_t *option="") const |
Draw a clone of this object in the current selected pad for instance with: gROOT->SetSelectedPad(gPad) . More... | |
virtual void | Dump () const |
Dump contents of object on stdout. More... | |
virtual void | Error (const char *method, const char *msgfmt,...) const |
Issue error message. More... | |
virtual void | Execute (const char *method, const char *params, Int_t *error=0) |
Execute method on this object with the given parameter string, e.g. More... | |
virtual void | Execute (TMethod *method, TObjArray *params, Int_t *error=0) |
Execute method on this object with parameters stored in the TObjArray. More... | |
virtual void | ExecuteEvent (Int_t event, Int_t px, Int_t py) |
Execute action corresponding to an event at (px,py). More... | |
virtual void | Fatal (const char *method, const char *msgfmt,...) const |
Issue fatal error message. More... | |
virtual TObject * | FindObject (const char *name) const |
Must be redefined in derived classes. More... | |
virtual TObject * | FindObject (const TObject *obj) const |
Must be redefined in derived classes. More... | |
virtual Option_t * | GetDrawOption () const |
Get option used by the graphics system to draw this object. More... | |
virtual const char * | GetIconName () const |
Returns mime type name of object. More... | |
virtual char * | GetObjectInfo (Int_t px, Int_t py) const |
Returns string containing info about the object at position (px,py). More... | |
virtual UInt_t | GetUniqueID () const |
Return the unique object id. More... | |
virtual Bool_t | HandleTimer (TTimer *timer) |
Execute action in response of a timer timing out. More... | |
virtual ULong_t | Hash () const |
Return hash value for this object. More... | |
virtual void | Info (const char *method, const char *msgfmt,...) const |
Issue info message. More... | |
virtual Bool_t | InheritsFrom (const char *classname) const |
Returns kTRUE if object inherits from class "classname". More... | |
virtual Bool_t | InheritsFrom (const TClass *cl) const |
Returns kTRUE if object inherits from TClass cl. More... | |
virtual void | Inspect () const |
Dump contents of this object in a graphics canvas. More... | |
void | InvertBit (UInt_t f) |
virtual Bool_t | IsEqual (const TObject *obj) const |
Default equal comparison (objects are equal if they have the same address in memory). More... | |
Bool_t | IsOnHeap () const |
virtual Bool_t | IsSortable () const |
Bool_t | IsZombie () const |
void | MayNotUse (const char *method) const |
Use this method to signal that a method (defined in a base class) may not be called in a derived class (in principle against good design since a child class should not provide less functionality than its parent, however, sometimes it is necessary). More... | |
virtual Bool_t | Notify () |
This method must be overridden to handle object notification. More... | |
void | Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const |
Use this method to declare a method obsolete. More... | |
void | operator delete (void *ptr) |
Operator delete. More... | |
void | operator delete[] (void *ptr) |
Operator delete []. More... | |
void * | operator new (size_t sz) |
void * | operator new (size_t sz, void *vp) |
void * | operator new[] (size_t sz) |
void * | operator new[] (size_t sz, void *vp) |
TObject & | operator= (const TObject &rhs) |
TObject assignment operator. More... | |
virtual void | Paint (Option_t *option="") |
This method must be overridden if a class wants to paint itself. More... | |
virtual void | Pop () |
Pop on object drawn in a pad to the top of the display list. More... | |
virtual Int_t | Read (const char *name) |
Read contents of object with specified name from the current directory. More... | |
virtual void | RecursiveRemove (TObject *obj) |
Recursively remove this object from a list. More... | |
void | ResetBit (UInt_t f) |
virtual void | SaveAs (const char *filename="", Option_t *option="") const |
Save this object in the file specified by filename. More... | |
virtual void | SavePrimitive (std::ostream &out, Option_t *option="") |
Save a primitive as a C++ statement(s) on output stream "out". More... | |
void | SetBit (UInt_t f, Bool_t set) |
Set or unset the user status bits as specified in f. More... | |
void | SetBit (UInt_t f) |
virtual void | SetDrawOption (Option_t *option="") |
Set drawing option for object. More... | |
virtual void | SetUniqueID (UInt_t uid) |
Set the unique object id. More... | |
virtual void | SysError (const char *method, const char *msgfmt,...) const |
Issue system error message. More... | |
Bool_t | TestBit (UInt_t f) const |
Int_t | TestBits (UInt_t f) const |
virtual void | UseCurrentStyle () |
Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. More... | |
virtual void | Warning (const char *method, const char *msgfmt,...) const |
Issue warning message. More... | |
virtual Int_t | Write (const char *name=0, Int_t option=0, Int_t bufsize=0) |
Write this object to the current directory. More... | |
virtual Int_t | Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const |
Write this object to the current directory. More... | |
Static Public Member Functions | |
static TMapFile * | Create (const char *name, Option_t *option="READ", Int_t size=kDefaultMapSize, const char *title="") |
Create a memory mapped file. More... | |
static void | SetMapAddress (Long_t addr) |
Set preferred map address. More... | |
static TMapFile * | WhichMapFile (void *addr) |
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static Long_t | GetDtorOnly () |
Return destructor only flag. More... | |
static Bool_t | GetObjectStat () |
Get status of object stat flag. More... | |
static void | SetDtorOnly (void *obj) |
Set destructor only flag. More... | |
static void | SetObjectStat (Bool_t stat) |
Turn on/off tracking of objects in the TObjectTable. More... | |
Protected Member Functions | |
TMapFile () | |
Default ctor. Does not much except setting some basic values. More... | |
TMapFile (const char *name, const char *title, Option_t *option, Int_t size, TMapFile *&newMapFile) | |
Create a memory mapped file. More... | |
TMapFile (const TMapFile &f, Long_t offset=0) | |
Private copy ctor. More... | |
Int_t | AcquireSemaphore () |
Acquire semaphore. Returns 0 if OK, -1 on error. More... | |
void | CreateSemaphore (Int_t pid=0) |
Create semaphore used for synchronizing access to shared memory. More... | |
void | DeleteSemaphore () |
Delete the semaphore. More... | |
TMapFile * | FindShadowMapFile () |
Returns shadow map file. More... | |
Int_t | GetBestBuffer () |
Return the best buffer size for objects in this file. More... | |
void | InitDirectory () |
Create the directory associated to this mapfile. More... | |
void | operator= (const TMapFile &rhs) |
Int_t | ReleaseSemaphore () |
Release semaphore. Returns 0 if OK, -1 on error. More... | |
TObject * | Remove (TObject *obj, Bool_t lock) |
Remove object from shared memory. More... | |
TObject * | Remove (const char *name, Bool_t lock) |
Remove object by name from shared memory. More... | |
void | SumBuffer (Int_t bufsize) |
Increment statistics for buffer sizes of objects in this file. More... | |
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virtual void | DoError (int level, const char *location, const char *fmt, va_list va) const |
Interface to ErrorHandler (protected). More... | |
void | MakeZombie () |
Static Protected Member Functions | |
static void * | MapToAddress () |
Return the base address at which we would like the next TMapFile's mapped data to start. More... | |
Private Attributes | |
ULong_t | fBaseAddr |
Base address of mapped memory region. More... | |
TList * | fBrowseList |
List of KeyMapFile objects. More... | |
TDirectory * | fDirectory |
Pointer to directory associated to this mapfile. More... | |
Int_t | fFd |
Descriptor of mapped file. More... | |
TMapRec * | fFirst |
List of streamed objects is shared memory. More... | |
TObject * | fGetting |
Don't deadlock in update mode, when from Get() Add() is called. More... | |
ULong_t | fhSemaphore |
HANDLE of WIN32 Mutex object to implement semaphore. More... | |
TMapRec * | fLast |
Last object in list of shared objects. More... | |
void * | fMmallocDesc |
Pointer to mmalloc descriptor. More... | |
char * | fName |
Name of mapped file. More... | |
Long_t | fOffset |
Offset in bytes for region mapped by reader. More... | |
char * | fOption |
Directory creation options. More... | |
Int_t | fSemaphore |
Modification semaphore (or getpid() for WIN32) More... | |
Int_t | fSize |
Original start size of memory mapped region. More... | |
Double_t | fSum2Buffer |
Sum of squares of buffer sizes of objects written so far. More... | |
Double_t | fSumBuffer |
Sum of buffer sizes of objects written sofar. More... | |
char * | fTitle |
Title of mapped file. More... | |
Int_t | fVersion |
ROOT version (or -1 for shadow map file) More... | |
Bool_t | fWritable |
TRUE if mapped file opened in RDWR mode. More... | |
Int_t | fWritten |
Number of objects written sofar. More... | |
Static Private Attributes | |
static Long_t | fgMapAddress = 0 |
Map to this address, set address via SetMapAddress() More... | |
static void * | fgMmallocDesc = 0 |
Used in Close() and operator delete() More... | |
Friends | |
class | TMapRec |
#include <TMapFile.h>
anonymous enum |
Enumerator | |
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kDefaultMapSize |
Definition at line 76 of file TMapFile.h.
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Default ctor. Does not much except setting some basic values.
Definition at line 199 of file TMapFile.cxx.
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Create a memory mapped file.
This opens a file (to which the memory will be mapped) and attaches a memory region to it. Option can be either: "NEW", "CREATE", "RECREATE", "UPDATE" or "READ" (see TFile). The default open mode is "READ". The size argument specifies the maximum size of shared memory file in bytes. This protected ctor is called via the static Create() method.
Definition at line 233 of file TMapFile.cxx.
Private copy ctor.
Used by the the ctor to create a new version of TMapFile in the memory mapped heap. It's main purpose is to correctly create the string data members.
Definition at line 516 of file TMapFile.cxx.
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Acquire semaphore. Returns 0 if OK, -1 on error.
Definition at line 872 of file TMapFile.cxx.
Add an object to the list of objects to be stored in shared memory.
To place the object actually into shared memory call Update().
Definition at line 590 of file TMapFile.cxx.
Browse contents of TMapFile.
Reimplemented from TObject.
Definition at line 1036 of file TMapFile.cxx.
Bool_t TMapFile::cd | ( | const char * | path = 0 | ) |
Cd to associated directory.
Definition at line 1063 of file TMapFile.cxx.
Close a mapped file.
First detach mapped memory then close file. No member functions of a TMapFile that was opened in write mode may be called after Close() (this includes, of course, "delete" which would call the dtors). The option="dtor" is only used when called via the ~TMapFile.
Definition at line 949 of file TMapFile.cxx.
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Create a memory mapped file.
This opens a file (to which the memory will be mapped) and attaches a memory region to it. Option can be either: "NEW", "CREATE", "RECREATE", "UPDATE" or "READ" (see TFile). The default open mode is "READ". The size argument specifies the maximum size of shared memory file in bytes. TMapFile's can only be created via this method. Create() enforces that a TMapFile is always on the memory mapped heap (when "NEW", "CREATE" or "RECREATE" are used).
Definition at line 1142 of file TMapFile.cxx.
Create semaphore used for synchronizing access to shared memory.
Definition at line 817 of file TMapFile.cxx.
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Delete the semaphore.
Definition at line 847 of file TMapFile.cxx.
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Returns shadow map file.
Definition at line 994 of file TMapFile.cxx.
Return pointer to object retrieved from shared memory.
The object must be deleted after use. If delObj is a pointer to a previously allocated object it will be deleted. Returns 0 in case object with the given name does not exist.
Definition at line 770 of file TMapFile.cxx.
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Definition at line 84 of file TMapFile.h.
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Return the best buffer size for objects in this file.
The best buffer size is estimated based on the current mean value and standard deviation of all objects written so far to this file. Returns mean value + one standard deviation.
Definition at line 1112 of file TMapFile.cxx.
void * TMapFile::GetBreakval | ( | ) | const |
Return the current location in the memory region for this malloc heap which represents the end of memory in use.
Returns 0 if map file was closed.
Definition at line 1124 of file TMapFile.cxx.
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Definition at line 86 of file TMapFile.h.
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Definition at line 87 of file TMapFile.h.
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Definition at line 93 of file TMapFile.h.
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Definition at line 94 of file TMapFile.h.
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Definition at line 88 of file TMapFile.h.
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Returns name of object.
This default method returns the class name. Classes that give objects a name should override this method.
Reimplemented from TObject.
Definition at line 89 of file TMapFile.h.
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Reimplemented from TObject.
Definition at line 91 of file TMapFile.h.
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Definition at line 90 of file TMapFile.h.
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Returns title of object.
This default method returns the class title (i.e. description). Classes that give objects a title should override this method.
Reimplemented from TObject.
Definition at line 92 of file TMapFile.h.
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Create the directory associated to this mapfile.
Definition at line 575 of file TMapFile.cxx.
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Returns kTRUE in case object is a folder (i.e. contains browsable lists).
Reimplemented from TObject.
Definition at line 1027 of file TMapFile.cxx.
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Definition at line 96 of file TMapFile.h.
List contents of TMapFile.
Reimplemented from TObject.
Definition at line 1073 of file TMapFile.cxx.
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Return the base address at which we would like the next TMapFile's mapped data to start.
For now, we let the system decide (start address 0). There are a lot of issues to deal with here to make this work reasonably, including:
Once created, a mmalloc heap that is to be mapped back in must be mapped at the original address. I.e. each TMapFile will expect to be remapped at it's original address. This becomes a problem if the desired address is already in use.
Definition at line 1201 of file TMapFile.cxx.
Need special "operator delete" in which we close the shared memory.
This has to be done after the dtor chain has been finished.
Definition at line 1217 of file TMapFile.cxx.
Definition at line 97 of file TMapFile.h.
Print some info about the mapped file.
Reimplemented from TObject.
Definition at line 1010 of file TMapFile.cxx.
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Release semaphore. Returns 0 if OK, -1 on error.
Definition at line 917 of file TMapFile.cxx.
Remove object from shared memory.
Returns pointer to removed object if successful, 0 otherwise.
Definition at line 669 of file TMapFile.cxx.
Remove object by name from shared memory.
Returns pointer to removed object if successful, 0 otherwise.
Definition at line 708 of file TMapFile.cxx.
Definition at line 104 of file TMapFile.h.
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Definition at line 105 of file TMapFile.h.
void TMapFile::RemoveAll | ( | ) |
Remove all objects from shared memory.
Definition at line 745 of file TMapFile.cxx.
Set preferred map address.
Find out preferred map address as follows:
Repeat this if more than one map file is being used. The above procedure allow programs using, e.g., different number of shared libraries (that cause the default mapping address to be different) to create shared memory regions in the same location without overwriting a shared library. The above assumes the consumer program is larger (i.e. has more shared memory occupied) than the producer. If this is not true inverse the procedure.
Definition at line 1179 of file TMapFile.cxx.
Increment statistics for buffer sizes of objects in this file.
Definition at line 1098 of file TMapFile.cxx.
Update an object (or all objects, if obj == 0) in shared memory.
Definition at line 629 of file TMapFile.cxx.
Definition at line 1227 of file TMapFile.cxx.
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Definition at line 28 of file TMapFile.h.
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Base address of mapped memory region.
Definition at line 37 of file TMapFile.h.
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List of KeyMapFile objects.
Definition at line 43 of file TMapFile.h.
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Pointer to directory associated to this mapfile.
Definition at line 42 of file TMapFile.h.
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Descriptor of mapped file.
Definition at line 31 of file TMapFile.h.
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List of streamed objects is shared memory.
Definition at line 39 of file TMapFile.h.
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Don't deadlock in update mode, when from Get() Add() is called.
Definition at line 47 of file TMapFile.h.
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Map to this address, set address via SetMapAddress()
Definition at line 52 of file TMapFile.h.
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Used in Close() and operator delete()
Definition at line 53 of file TMapFile.h.
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HANDLE of WIN32 Mutex object to implement semaphore.
Definition at line 46 of file TMapFile.h.
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Last object in list of shared objects.
Definition at line 40 of file TMapFile.h.
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Pointer to mmalloc descriptor.
Definition at line 36 of file TMapFile.h.
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Name of mapped file.
Definition at line 33 of file TMapFile.h.
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Offset in bytes for region mapped by reader.
Definition at line 41 of file TMapFile.h.
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Directory creation options.
Definition at line 35 of file TMapFile.h.
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Modification semaphore (or getpid() for WIN32)
Definition at line 45 of file TMapFile.h.
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Original start size of memory mapped region.
Definition at line 38 of file TMapFile.h.
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Sum of squares of buffer sizes of objects written so far.
Definition at line 50 of file TMapFile.h.
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Sum of buffer sizes of objects written sofar.
Definition at line 49 of file TMapFile.h.
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Title of mapped file.
Definition at line 34 of file TMapFile.h.
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ROOT version (or -1 for shadow map file)
Definition at line 32 of file TMapFile.h.
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TRUE if mapped file opened in RDWR mode.
Definition at line 44 of file TMapFile.h.
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Number of objects written sofar.
Definition at line 48 of file TMapFile.h.