ROOT
6.06/09
Reference Guide
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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 34 of file TMapFile.h.
Public Types | |
enum | { kDefaultMapSize = 0x80000 } |
Public Types inherited from TObject | |
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) } |
enum | { kIsOnHeap = 0x01000000, kNotDeleted = 0x02000000, kZombie = 0x04000000, kBitMask = 0x00ffffff } |
enum | { kSingleKey = BIT(0), kOverwrite = BIT(1), kWriteDelete = BIT(2) } |
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 | operator delete (void *vp) |
Need special "operator delete" in which we close the shared memory. More... | |
void | Browse (TBrowser *b) |
Browse contents of TMapFile. More... | |
void | Close (Option_t *option="") |
Close a mapped file. 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 |
void * | GetMmallocDesc () const |
const char * | GetName () const |
Returns name of object. More... | |
Int_t | GetSize () const |
const char * | GetOption () const |
const char * | GetTitle () const |
Returns title of object. More... | |
TMapRec * | GetFirst () const |
TMapRec * | GetLast () const |
Bool_t | IsFolder () const |
Returns kTRUE in case object is a folder (i.e. contains browsable lists). More... | |
Bool_t | IsWritable () const |
void * | OrgAddress (void *addr) const |
void | Print (Option_t *option="") const |
Print some info about the mapped file. More... | |
void | ls (Option_t *option="") const |
List contents of TMapFile. More... | |
Bool_t | cd (const char *path=0) |
Cd to associated directory. 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 | Update (TObject *obj=0) |
Update an object (or all objects, if obj == 0) in shared memory. More... | |
TObject * | Remove (TObject *obj) |
TObject * | Remove (const char *name) |
void | RemoveAll () |
Remove all objects from shared memory. More... | |
TObject * | Get (const char *name, TObject *retObj=0) |
Return pointer to object retrieved from shared memory. More... | |
Public Member Functions inherited from TObject | |
TObject () | |
TObject (const TObject &object) | |
TObject copy ctor. More... | |
TObject & | operator= (const TObject &rhs) |
TObject assignment operator. More... | |
virtual | ~TObject () |
TObject destructor. 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 pad. More... | |
virtual void | Dump () const |
Dump contents of object on stdout. 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 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 UInt_t | GetUniqueID () const |
Return the unique object id. 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 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 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... | |
virtual Bool_t | IsEqual (const TObject *obj) const |
Default equal comparison (objects are equal if they have the same address in memory). More... | |
virtual Bool_t | IsSortable () const |
Bool_t | IsOnHeap () const |
Bool_t | IsZombie () const |
virtual Bool_t | Notify () |
This method must be overridden to handle object notification. 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... | |
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... | |
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 | UseCurrentStyle () |
Set current style settings in this object This function is called when either TCanvas::UseCurrentStyle or TROOT::ForceStyle have been invoked. 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... | |
void * | operator new (size_t sz) |
void * | operator new[] (size_t sz) |
void * | operator new (size_t sz, void *vp) |
void * | operator new[] (size_t sz, void *vp) |
void | operator delete (void *ptr) |
Operator delete. More... | |
void | operator delete[] (void *ptr) |
Operator delete []. 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) |
void | ResetBit (UInt_t f) |
Bool_t | TestBit (UInt_t f) const |
Int_t | TestBits (UInt_t f) const |
void | InvertBit (UInt_t f) |
virtual void | Info (const char *method, const char *msgfmt,...) const |
Issue info message. More... | |
virtual void | Warning (const char *method, const char *msgfmt,...) const |
Issue warning message. More... | |
virtual void | Error (const char *method, const char *msgfmt,...) const |
Issue error message. More... | |
virtual void | SysError (const char *method, const char *msgfmt,...) const |
Issue system error message. More... | |
virtual void | Fatal (const char *method, const char *msgfmt,...) const |
Issue fatal error message. 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... | |
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... | |
void | Obsolete (const char *method, const char *asOfVers, const char *removedFromVers) const |
Use this method to declare a method obsolete. 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 TMapFile * | WhichMapFile (void *addr) |
static void | SetMapAddress (Long_t addr) |
Set preferred map address. More... | |
Static Public Member Functions inherited from TObject | |
static Long_t | GetDtorOnly () |
Return destructor only flag. More... | |
static void | SetDtorOnly (void *obj) |
Set destructor only flag. More... | |
static Bool_t | GetObjectStat () |
Get status of object stat flag. More... | |
static void | SetObjectStat (Bool_t stat) |
Turn on/off tracking of objects in the TObjectTable. More... | |
Protected Member Functions | |
TMapFile () | |
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... | |
void | operator= (const TMapFile &rhs) |
TMapFile * | FindShadowMapFile () |
Returns shadow map file. More... | |
void | InitDirectory () |
Create the directory associated to this mapfile. 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... | |
Int_t | GetBestBuffer () |
Return the best buffer size for objects in this file. More... | |
void | CreateSemaphore (Int_t pid=0) |
Create semaphore used for synchronizing access to shared memory. More... | |
Int_t | AcquireSemaphore () |
Acquire semaphore. Returns 0 if OK, -1 on error. More... | |
Int_t | ReleaseSemaphore () |
Release semaphore. Returns 0 if OK, -1 on error. More... | |
void | DeleteSemaphore () |
Delete the semaphore. More... | |
Protected Member Functions inherited from TObject | |
void | MakeZombie () |
virtual void | DoError (int level, const char *location, const char *fmt, va_list va) const |
Interface to ErrorHandler (protected). More... | |
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 | |
Int_t | fFd |
Descriptor of mapped file. More... | |
Int_t | fVersion |
ROOT version (or -1 for shadow map file) More... | |
char * | fName |
Name of mapped file. More... | |
char * | fTitle |
Title of mapped file. More... | |
char * | fOption |
Directory creation options. More... | |
void * | fMmallocDesc |
Pointer to mmalloc descriptor. More... | |
ULong_t | fBaseAddr |
Base address of mapped memory region. More... | |
Int_t | fSize |
Original start size of memory mapped region. More... | |
TMapRec * | fFirst |
List of streamed objects is shared memory. More... | |
TMapRec * | fLast |
Last object in list of shared objects. More... | |
Long_t | fOffset |
Offset in bytes for region mapped by reader. More... | |
TDirectory * | fDirectory |
Pointer to directory associated to this mapfile. More... | |
TList * | fBrowseList |
List of KeyMapFile objects. More... | |
Bool_t | fWritable |
TRUE if mapped file opened in RDWR mode. More... | |
Int_t | fSemaphore |
Modification semaphore (or getpid() for WIN32) More... | |
ULong_t | fhSemaphore |
HANDLE of WIN32 Mutex object to implement semaphore. More... | |
TObject * | fGetting |
Don't deadlock in update mode, when from Get() Add() is called. More... | |
Int_t | fWritten |
Number of objects written sofar. More... | |
Double_t | fSumBuffer |
Sum of buffer sizes of objects written sofar. More... | |
Double_t | fSum2Buffer |
Sum of squares of buffer sizes of objects written so far. 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 84 of file TMapFile.h.
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Referenced by Create(), and TMapFile().
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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 204 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 487 of file TMapFile.cxx.
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Acquire semaphore. Returns 0 if OK, -1 on error.
Definition at line 843 of file TMapFile.cxx.
Referenced by Add(), Browse(), Get(), Remove(), RemoveAll(), and Update().
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 561 of file TMapFile.cxx.
Referenced by TDirectoryFile::Append().
Browse contents of TMapFile.
Reimplemented from TObject.
Definition at line 1007 of file TMapFile.cxx.
Bool_t TMapFile::cd | ( | const char * | path = 0 | ) |
Cd to associated directory.
Definition at line 1034 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 920 of file TMapFile.cxx.
Referenced by ~TMapFile().
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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 1104 of file TMapFile.cxx.
Create semaphore used for synchronizing access to shared memory.
Definition at line 788 of file TMapFile.cxx.
Referenced by TMapFile().
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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 741 of file TMapFile.cxx.
Referenced by TKeyMapFile::Browse().
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Definition at line 92 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 1083 of file TMapFile.cxx.
Referenced by Update().
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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 166 of file TMapFile.h.
Referenced by Print(), and WhichMapFile().
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Definition at line 94 of file TMapFile.h.
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Definition at line 95 of file TMapFile.h.
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Definition at line 101 of file TMapFile.h.
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Definition at line 102 of file TMapFile.h.
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Definition at line 96 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 97 of file TMapFile.h.
Referenced by InitDirectory().
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Reimplemented from TObject.
Definition at line 99 of file TMapFile.h.
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Definition at line 98 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 100 of file TMapFile.h.
Referenced by InitDirectory().
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Create the directory associated to this mapfile.
Definition at line 546 of file TMapFile.cxx.
Referenced by TMapFile().
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Returns kTRUE in case object is a folder (i.e. contains browsable lists).
Reimplemented from TObject.
Definition at line 998 of file TMapFile.cxx.
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Definition at line 104 of file TMapFile.h.
List contents of TMapFile.
Reimplemented from TObject.
Definition at line 1044 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 1163 of file TMapFile.cxx.
Referenced by TMapFile().
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 1179 of file TMapFile.cxx.
Definition at line 105 of file TMapFile.h.
Print some info about the mapped file.
Reimplemented from TObject.
Definition at line 981 of file TMapFile.cxx.
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Release semaphore. Returns 0 if OK, -1 on error.
Definition at line 888 of file TMapFile.cxx.
Referenced by Add(), Browse(), Get(), Remove(), RemoveAll(), and Update().
Remove object from shared memory.
Returns pointer to removed object if successful, 0 otherwise.
Definition at line 640 of file TMapFile.cxx.
Referenced by Add().
Remove object by name from shared memory.
Returns pointer to removed object if successful, 0 otherwise.
Definition at line 679 of file TMapFile.cxx.
Definition at line 112 of file TMapFile.h.
Referenced by Remove().
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Definition at line 113 of file TMapFile.h.
Referenced by Remove().
void TMapFile::RemoveAll | ( | ) |
Remove all objects from shared memory.
Definition at line 716 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 1141 of file TMapFile.cxx.
Increment statistics for buffer sizes of objects in this file.
Definition at line 1069 of file TMapFile.cxx.
Referenced by Update().
Update an object (or all objects, if obj == 0) in shared memory.
Definition at line 600 of file TMapFile.cxx.
Definition at line 174 of file TMapFile.h.
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Definition at line 36 of file TMapFile.h.
Referenced by Add().
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Base address of mapped memory region.
Definition at line 45 of file TMapFile.h.
Referenced by FindShadowMapFile(), GetBaseAddr(), Print(), TMapFile(), and WhichMapFile().
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List of KeyMapFile objects.
Definition at line 51 of file TMapFile.h.
Referenced by Browse(), TMapFile(), and ~TMapFile().
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Pointer to directory associated to this mapfile.
Definition at line 50 of file TMapFile.h.
Referenced by cd(), GetDirectory(), InitDirectory(), TMapFile(), and ~TMapFile().
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Descriptor of mapped file.
Definition at line 39 of file TMapFile.h.
Referenced by Close(), GetFd(), and TMapFile().
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List of streamed objects is shared memory.
Definition at line 47 of file TMapFile.h.
Referenced by Add(), ls(), Remove(), RemoveAll(), TMapFile(), and Update().
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Don't deadlock in update mode, when from Get() Add() is called.
Definition at line 55 of file TMapFile.h.
Referenced by Add(), Get(), and TMapFile().
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Map to this address, set address via SetMapAddress()
Definition at line 60 of file TMapFile.h.
Referenced by MapToAddress(), and SetMapAddress().
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Used in Close() and operator delete()
Definition at line 61 of file TMapFile.h.
Referenced by ~TMapFile().
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HANDLE of WIN32 Mutex object to implement semaphore.
Definition at line 54 of file TMapFile.h.
Referenced by AcquireSemaphore(), DeleteSemaphore(), ReleaseSemaphore(), and TMapFile().
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Last object in list of shared objects.
Definition at line 48 of file TMapFile.h.
Referenced by Add(), Remove(), RemoveAll(), and TMapFile().
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Pointer to mmalloc descriptor.
Definition at line 44 of file TMapFile.h.
Referenced by AcquireSemaphore(), Add(), Browse(), Close(), Get(), GetBreakval(), GetMmallocDesc(), IsFolder(), ls(), Print(), Remove(), RemoveAll(), TMapFile(), Update(), and ~TMapFile().
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Name of mapped file.
Definition at line 41 of file TMapFile.h.
Referenced by GetName(), Print(), and TMapFile().
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Offset in bytes for region mapped by reader.
Definition at line 49 of file TMapFile.h.
Referenced by Browse(), Get(), ls(), TMapFile(), and WhichMapFile().
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Directory creation options.
Definition at line 43 of file TMapFile.h.
Referenced by GetOption(), Print(), and TMapFile().
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Modification semaphore (or getpid() for WIN32)
Definition at line 53 of file TMapFile.h.
Referenced by AcquireSemaphore(), DeleteSemaphore(), ReleaseSemaphore(), and TMapFile().
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Original start size of memory mapped region.
Definition at line 46 of file TMapFile.h.
Referenced by FindShadowMapFile(), GetSize(), and TMapFile().
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Sum of squares of buffer sizes of objects written so far.
Definition at line 58 of file TMapFile.h.
Referenced by GetBestBuffer(), SumBuffer(), and TMapFile().
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Sum of buffer sizes of objects written sofar.
Definition at line 57 of file TMapFile.h.
Referenced by GetBestBuffer(), SumBuffer(), and TMapFile().
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Title of mapped file.
Definition at line 42 of file TMapFile.h.
Referenced by GetTitle(), Print(), and TMapFile().
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ROOT version (or -1 for shadow map file)
Definition at line 40 of file TMapFile.h.
Referenced by FindShadowMapFile(), IsFolder(), TMapFile(), and ~TMapFile().
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TRUE if mapped file opened in RDWR mode.
Definition at line 52 of file TMapFile.h.
Referenced by AcquireSemaphore(), Add(), Close(), IsWritable(), Remove(), RemoveAll(), TMapFile(), Update(), and ~TMapFile().
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Number of objects written sofar.
Definition at line 56 of file TMapFile.h.
Referenced by GetBestBuffer(), SumBuffer(), and TMapFile().