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:

One could allocate an object directly in shared memory in the producer, but the consumer still has to copy the object from shared memory into a local object which has the correct vtbl pointer for that process (copy ctor's can be used for creating the local copy).
Another possibility is to only allow objects without virtual functions in shared memory (like simple C structs), or to forbid (how?) the consumer from calling any virtual functions of the objects in shared memory.
A last option is to copy the object internals to shared memory and copy them again from there. This is what is done in the TMapFile (using the object Streamer() to make a deep copy).

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 25 of file TMapFile.h.

Public Types
enum	{ kDefaultMapSize = 0x80000 }

Public Types inherited from TObject
enum	{ kIsOnHeap = 0x01000000 , kNotDeleted = 0x02000000 , kZombie = 0x04000000 , kInconsistent = 0x08000000 , kBitMask = 0x00ffffff }

enum	{ kSingleKey = BIT(0) , kOverwrite = BIT(1) , kWriteDelete = BIT(2) }

enum	EDeprecatedStatusBits { kObjInCanvas = BIT(3) }

enum	EStatusBits { kCanDelete = BIT(0) , kMustCleanup = 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.

void	Add (const TObject obj, const char name="")
	Add an object to the list of objects to be stored in shared memory.

void	Browse (TBrowser *b)
	Browse contents of TMapFile.

Bool_t	cd (const char *path=0)
	Cd to associated directory.

void	Close (Option_t *option="")
	Close a mapped file.

TObject *	Get (const char name, TObject retObj=nullptr)
	Return pointer to object retrieved from shared memory.

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.

TDirectory *	GetDirectory () const

Int_t	GetFd () const

TMapRec *	GetFirst () const

TMapRec *	GetLast () const

void *	GetMmallocDesc () const

const char *	GetName () const
	Returns name of object.

const char *	GetOption () const

Int_t	GetSize () const

const char *	GetTitle () const
	Returns title of object.

Bool_t	IsFolder () const
	Returns kTRUE in case object is a folder (i.e. contains browsable lists).

Bool_t	IsWritable () const

void	ls (Option_t *option="") const
	List contents of TMapFile.

void	operator delete (void *vp)
	Need special "operator delete" in which we close the shared memory.

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)

void *	OrgAddress (void *addr) const

void	Print (Option_t *option="") const
	Print some info about the mapped file.

TObject *	Remove (const char *name)

TObject *	Remove (TObject *obj)

void	RemoveAll ()
	Remove all objects from shared memory.

void	Update (TObject *obj=0)
	Update an object (or all objects, if obj == 0) in shared memory.

Public Member Functions inherited from TObject
	TObject ()
	TObject constructor.

	TObject (const TObject &object)
	TObject copy ctor.

virtual	~TObject ()
	TObject destructor.

void	AbstractMethod (const char *method) const
	Use this method to implement an "abstract" method that you don't want to leave purely abstract.

virtual void	AppendPad (Option_t *option="")
	Append graphics object to current pad.

ULong_t	CheckedHash ()
	Check and record whether this class has a consistent Hash/RecursiveRemove setup (*) and then return the regular Hash value for this object.

virtual const char *	ClassName () const
	Returns name of class to which the object belongs.

virtual void	Clear (Option_t *="")

virtual TObject *	Clone (const char *newname="") const
	Make a clone of an object using the Streamer facility.

virtual Int_t	Compare (const TObject *obj) const
	Compare abstract method.

virtual void	Copy (TObject &object) const
	Copy this to obj.

virtual void	Delete (Option_t *option="")
	Delete this object.

virtual Int_t	DistancetoPrimitive (Int_t px, Int_t py)
	Computes distance from point (px,py) to the object.

virtual void	Draw (Option_t *option="")
	Default Draw method for all objects.

virtual void	DrawClass () const
	Draw class inheritance tree of the class to which this object belongs.

virtual TObject *	DrawClone (Option_t *option="") const
	Draw a clone of this object in the current selected pad for instance with: `gROOT->SetSelectedPad(gPad)`.

virtual void	Dump () const
	Dump contents of object on stdout.

virtual void	Error (const char method, const char msgfmt,...) const
	Issue error message.

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.

virtual void	Execute (TMethod method, TObjArray params, Int_t *error=0)
	Execute method on this object with parameters stored in the TObjArray.

virtual void	ExecuteEvent (Int_t event, Int_t px, Int_t py)
	Execute action corresponding to an event at (px,py).

virtual void	Fatal (const char method, const char msgfmt,...) const
	Issue fatal error message.

virtual TObject *	FindObject (const char *name) const
	Must be redefined in derived classes.

virtual TObject *	FindObject (const TObject *obj) const
	Must be redefined in derived classes.

virtual Option_t *	GetDrawOption () const
	Get option used by the graphics system to draw this object.

virtual const char *	GetIconName () const
	Returns mime type name of object.

virtual char *	GetObjectInfo (Int_t px, Int_t py) const
	Returns string containing info about the object at position (px,py).

virtual UInt_t	GetUniqueID () const
	Return the unique object id.

virtual Bool_t	HandleTimer (TTimer *timer)
	Execute action in response of a timer timing out.

virtual ULong_t	Hash () const
	Return hash value for this object.

Bool_t	HasInconsistentHash () const
	Return true is the type of this object is known to have an inconsistent setup for Hash and RecursiveRemove (i.e.

virtual void	Info (const char method, const char msgfmt,...) const
	Issue info message.

virtual Bool_t	InheritsFrom (const char *classname) const
	Returns kTRUE if object inherits from class "classname".

virtual Bool_t	InheritsFrom (const TClass *cl) const
	Returns kTRUE if object inherits from TClass cl.

virtual void	Inspect () const
	Dump contents of this object in a graphics canvas.

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).

R__ALWAYS_INLINE Bool_t	IsOnHeap () const

virtual Bool_t	IsSortable () const

R__ALWAYS_INLINE 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).

virtual Bool_t	Notify ()
	This method must be overridden to handle object notification.

void	Obsolete (const char method, const char asOfVers, const char *removedFromVers) const
	Use this method to declare a method obsolete.

void	operator delete (void *ptr)
	Operator delete.

void	operator delete[] (void *ptr)
	Operator delete [].

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.

virtual void	Paint (Option_t *option="")
	This method must be overridden if a class wants to paint itself.

virtual void	Pop ()
	Pop on object drawn in a pad to the top of the display list.

virtual Int_t	Read (const char *name)
	Read contents of object with specified name from the current directory.

virtual void	RecursiveRemove (TObject *obj)
	Recursively remove this object from a list.

void	ResetBit (UInt_t f)

virtual void	SaveAs (const char filename="", Option_t option="") const
	Save this object in the file specified by filename.

virtual void	SavePrimitive (std::ostream &out, Option_t *option="")
	Save a primitive as a C++ statement(s) on output stream "out".

void	SetBit (UInt_t f)

void	SetBit (UInt_t f, Bool_t set)
	Set or unset the user status bits as specified in f.

virtual void	SetDrawOption (Option_t *option="")
	Set drawing option for object.

virtual void	SetUniqueID (UInt_t uid)
	Set the unique object id.

virtual void	SysError (const char method, const char msgfmt,...) const
	Issue system error message.

R__ALWAYS_INLINE 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.

virtual void	Warning (const char method, const char msgfmt,...) const
	Issue warning message.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0)
	Write this object to the current directory.

virtual Int_t	Write (const char *name=0, Int_t option=0, Int_t bufsize=0) const
	Write this object to the current directory.

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.

static void	SetMapAddress (Long_t addr)
	Set preferred map address.

static TMapFile *	WhichMapFile (void *addr)

Static Public Member Functions inherited from TObject
static Long_t	GetDtorOnly ()
	Return destructor only flag.

static Bool_t	GetObjectStat ()
	Get status of object stat flag.

static void	SetDtorOnly (void *obj)
	Set destructor only flag.

static void	SetObjectStat (Bool_t stat)
	Turn on/off tracking of objects in the TObjectTable.

Protected Member Functions
	TMapFile ()
	Default ctor. Does not much except setting some basic values.

	TMapFile (const char name, const char title, Option_t option, Int_t size, TMapFile &newMapFile)
	Create a memory mapped file.

	TMapFile (const TMapFile &f, Long_t offset=0)
	Private copy ctor.

Int_t	AcquireSemaphore ()
	Acquire semaphore. Returns 0 if OK, -1 on error.

void	CreateSemaphore (Int_t pid=0)
	Create semaphore used for synchronizing access to shared memory.

void	DeleteSemaphore ()
	Delete the semaphore.

TMapFile *	FindShadowMapFile ()
	Returns shadow map file.

Int_t	GetBestBuffer ()
	Return the best buffer size for objects in this file.

void	InitDirectory ()
	Create the directory associated to this mapfile.

TMapFile &	operator= (const TMapFile &rhs)=delete

Int_t	ReleaseSemaphore ()
	Release semaphore. Returns 0 if OK, -1 on error.

TObject *	Remove (const char *name, Bool_t lock)
	Remove object by name from shared memory.

TObject *	Remove (TObject *obj, Bool_t lock)
	Remove object from shared memory.

void	SumBuffer (Int_t bufsize)
	Increment statistics for buffer sizes of objects in this file.

Protected Member Functions inherited from TObject
virtual void	DoError (int level, const char location, const char fmt, va_list va) const
	Interface to ErrorHandler (protected).

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.

Private Attributes
ULong_t	fBaseAddr
	Base address of mapped memory region.

TList *	fBrowseList
	List of KeyMapFile objects.

TDirectory *	fDirectory
	Pointer to directory associated to this mapfile.

Int_t	fFd
	Descriptor of mapped file.

TMapRec *	fFirst
	List of streamed objects is shared memory.

TObject *	fGetting
	Don't deadlock in update mode, when from Get() Add() is called.

ULong_t	fhSemaphore
	HANDLE of WIN32 Mutex object to implement semaphore.

TMapRec *	fLast
	Last object in list of shared objects.

void *	fMmallocDesc
	Pointer to mmalloc descriptor.

char *	fName
	Name of mapped file.

Long_t	fOffset
	Offset in bytes for region mapped by reader.

char *	fOption
	Directory creation options.

Int_t	fSemaphore
	Modification semaphore (or getpid() for WIN32)

Int_t	fSize
	Original start size of memory mapped region.

Double_t	fSum2Buffer
	Sum of squares of buffer sizes of objects written so far.

Double_t	fSumBuffer
	Sum of buffer sizes of objects written sofar.

char *	fTitle
	Title of mapped file.

Int_t	fVersion
	ROOT version (or -1 for shadow map file)

Bool_t	fWritable
	TRUE if mapped file opened in RDWR mode.

Int_t	fWritten
	Number of objects written sofar.

Static Private Attributes
static Long_t	fgMapAddress = 0
	Map to this address, set address via SetMapAddress()

static void *	fgMmallocDesc = 0
	Used in Close() and operator delete()

Friends
class	TMapRec

Additional Inherited Members
Protected Types inherited from TObject
enum	{ kOnlyPrepStep = BIT(3) }

#include <TMapFile.h>

Inheritance diagram for TMapFile:

[legend]

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Enumerator
kDefaultMapSize

Definition at line 76 of file TMapFile.h.

Constructor & Destructor Documentation

◆ TMapFile() [1/3]

TMapFile::TMapFile ( )

protected

Default ctor. Does not much except setting some basic values.

Definition at line 200 of file TMapFile.cxx.

◆ TMapFile() [2/3]

TMapFile::TMapFile	(	const char *	name,
		const char *	title,
		Option_t *	option,
		Int_t	size,
		TMapFile *&	newMapFile
	)

protected

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 234 of file TMapFile.cxx.

◆ TMapFile() [3/3]

TMapFile::TMapFile	(	const TMapFile &	f,
		Long_t	offset = `0`
	)

protected

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 515 of file TMapFile.cxx.

◆ ~TMapFile()

TMapFile::~TMapFile ( )

virtual

TMapFiles may not be deleted, since we want to keep the complete TMapFile object in the mapped file for later re-use.

To enforce this the delete operator has been made private. Use Close() to properly terminate a TMapFile (also done via the TROOT dtor).

Definition at line 549 of file TMapFile.cxx.

Member Function Documentation

◆ AcquireSemaphore()

Int_t TMapFile::AcquireSemaphore ( )

protected

Acquire semaphore. Returns 0 if OK, -1 on error.

Definition at line 879 of file TMapFile.cxx.

◆ Add()

void TMapFile::Add	(	const TObject *	obj,
		const char *	name = `""`
	)

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 597 of file TMapFile.cxx.

◆ Browse()

void TMapFile::Browse ( TBrowser * b )

virtual

Browse contents of TMapFile.

Reimplemented from TObject.

Definition at line 1043 of file TMapFile.cxx.

◆ cd()

Bool_t TMapFile::cd ( const char * path = 0 )

Cd to associated directory.

Definition at line 1070 of file TMapFile.cxx.

◆ Close()

void TMapFile::Close ( Option_t * option = "" )

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 956 of file TMapFile.cxx.

◆ Create()

TMapFile * TMapFile::Create	(	const char *	name,
		Option_t *	option = `"READ"`,
		Int_t	size = `kDefaultMapSize`,
		const char *	title = `""`
	)

static

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 1149 of file TMapFile.cxx.

◆ CreateSemaphore()

void TMapFile::CreateSemaphore ( Int_t pid = 0 )

protected

Create semaphore used for synchronizing access to shared memory.

Definition at line 824 of file TMapFile.cxx.

◆ DeleteSemaphore()

void TMapFile::DeleteSemaphore ( )

protected

Delete the semaphore.

Definition at line 854 of file TMapFile.cxx.

◆ FindShadowMapFile()

TMapFile * TMapFile::FindShadowMapFile ( )

protected

Returns shadow map file.

Definition at line 1001 of file TMapFile.cxx.

◆ Get()

TObject * TMapFile::Get	(	const char *	name,
		TObject *	delObj = `nullptr`
	)

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 777 of file TMapFile.cxx.

◆ GetBaseAddr()

void * TMapFile::GetBaseAddr ( ) const

inline

Definition at line 88 of file TMapFile.h.

◆ GetBestBuffer()

Int_t TMapFile::GetBestBuffer ( )

protected

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 1119 of file TMapFile.cxx.

◆ GetBreakval()

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 1131 of file TMapFile.cxx.

◆ GetDirectory()

TDirectory * TMapFile::GetDirectory ( ) const

inline

Definition at line 90 of file TMapFile.h.

◆ GetFd()

Int_t TMapFile::GetFd ( ) const

inline

Definition at line 91 of file TMapFile.h.

◆ GetFirst()

TMapRec * TMapFile::GetFirst ( ) const

inline

Definition at line 97 of file TMapFile.h.

◆ GetLast()

TMapRec * TMapFile::GetLast ( ) const

inline

Definition at line 98 of file TMapFile.h.

◆ GetMmallocDesc()

void * TMapFile::GetMmallocDesc ( ) const

inline

Definition at line 92 of file TMapFile.h.

◆ GetName()

const char * TMapFile::GetName ( ) const

inlinevirtual

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 93 of file TMapFile.h.

◆ GetOption()

const char * TMapFile::GetOption ( ) const

inlinevirtual

Reimplemented from TObject.

Definition at line 95 of file TMapFile.h.

◆ GetSize()

Int_t TMapFile::GetSize ( ) const

inline

Definition at line 94 of file TMapFile.h.

◆ GetTitle()

const char * TMapFile::GetTitle ( ) const

inlinevirtual

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 96 of file TMapFile.h.

◆ InitDirectory()

void TMapFile::InitDirectory ( )

protected

Create the directory associated to this mapfile.

Definition at line 582 of file TMapFile.cxx.

◆ IsFolder()

Bool_t TMapFile::IsFolder ( ) const

virtual

Returns kTRUE in case object is a folder (i.e. contains browsable lists).

Reimplemented from TObject.

Definition at line 1034 of file TMapFile.cxx.

◆ IsWritable()

Bool_t TMapFile::IsWritable ( ) const

inline

Definition at line 100 of file TMapFile.h.

◆ ls()

void TMapFile::ls ( Option_t * option = "" ) const

virtual

List contents of TMapFile.

Reimplemented from TObject.

Definition at line 1080 of file TMapFile.cxx.

◆ MapToAddress()

void * TMapFile::MapToAddress ( )

staticprotected

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:

Avoid memory collisions with existing mapped address spaces
Reclaim address spaces when their mmalloc heaps are unmapped
When mmalloc heaps are shared between processes they have to be mapped at the same addresses in each

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 1208 of file TMapFile.cxx.

◆ operator delete()

void TMapFile::operator delete ( void * ptr )

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 1224 of file TMapFile.cxx.

◆ operator new() [1/2]

void * TMapFile::operator new ( size_t sz )

inline

Definition at line 80 of file TMapFile.h.

◆ operator new() [2/2]

void * TMapFile::operator new	(	size_t	sz,
		void *	vp
	)

inline

Definition at line 82 of file TMapFile.h.

◆ operator new[]() [1/2]

void * TMapFile::operator new[] ( size_t sz )

inline

Definition at line 81 of file TMapFile.h.

◆ operator new[]() [2/2]

void * TMapFile::operator new[]	(	size_t	sz,
		void *	vp
	)

inline

Definition at line 83 of file TMapFile.h.

◆ operator=()

TMapFile & TMapFile::operator= ( const TMapFile & rhs )

protecteddelete

◆ OrgAddress()

void * TMapFile::OrgAddress ( void * addr ) const

inline

Definition at line 101 of file TMapFile.h.

◆ Print()

void TMapFile::Print ( Option_t * option = "" ) const

virtual

Print some info about the mapped file.

Reimplemented from TObject.

Definition at line 1017 of file TMapFile.cxx.

◆ ReleaseSemaphore()

Int_t TMapFile::ReleaseSemaphore ( )

protected

Release semaphore. Returns 0 if OK, -1 on error.

Definition at line 924 of file TMapFile.cxx.

◆ Remove() [1/4]

TObject * TMapFile::Remove ( const char * name )

inline

Definition at line 109 of file TMapFile.h.

◆ Remove() [2/4]

TObject * TMapFile::Remove	(	const char *	name,
		Bool_t	lock
	)

protected

Remove object by name from shared memory.

Returns pointer to removed object if successful, 0 otherwise.

Definition at line 715 of file TMapFile.cxx.

◆ Remove() [3/4]

TObject * TMapFile::Remove ( TObject * obj )

inline

Definition at line 108 of file TMapFile.h.

◆ Remove() [4/4]

TObject * TMapFile::Remove	(	TObject *	obj,
		Bool_t	lock
	)

protected

Remove object from shared memory.

Returns pointer to removed object if successful, 0 otherwise.

Definition at line 676 of file TMapFile.cxx.

◆ RemoveAll()

void TMapFile::RemoveAll ( )

Remove all objects from shared memory.

Definition at line 752 of file TMapFile.cxx.

◆ SetMapAddress()

void TMapFile::SetMapAddress ( Long_t addr )

static

Set preferred map address.

Find out preferred map address as follows:

Run consumer program to find the preferred map address. Remember begin of mapped region, i.e. 0x40b4c000
$ root

root [0] m = TMapFile::Create("dummy.map", "recreate", 10000000);

root [1] m.Print()

Memory mapped file: dummy.map

Title:

Option: CREATE

Mapped Memory region: 0x40b4c000 - 0x40d95f00 (2.29 MB)

Current breakval: 0x40b53000

root [2] .q

$ rm dummy.map

q
float * q
Definition THbookFile.cxx:89

TMapFile::Create
static TMapFile * Create(const char *name, Option_t *option="READ", Int_t size=kDefaultMapSize, const char *title="")
Create a memory mapped file.
Definition TMapFile.cxx:1149

file
Definition file.py:1

m
auto * m
Definition textangle.C:8
Add to producer program, just before creating the TMapFile: TMapFile::SetMapAddress(0x40b4c000);

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 1186 of file TMapFile.cxx.

◆ SumBuffer()

void TMapFile::SumBuffer ( Int_t bufsize )

protected

Increment statistics for buffer sizes of objects in this file.

Definition at line 1105 of file TMapFile.cxx.

◆ Update()

void TMapFile::Update ( TObject * obj = 0 )

Update an object (or all objects, if obj == 0) in shared memory.

Definition at line 636 of file TMapFile.cxx.

◆ WhichMapFile()

TMapFile * TMapFile::WhichMapFile ( void * addr )

static

Definition at line 1234 of file TMapFile.cxx.

Friends And Related Symbol Documentation

◆ TMapRec

friend class TMapRec

friend

Definition at line 27 of file TMapFile.h.

Member Data Documentation

◆ fBaseAddr

ULong_t TMapFile::fBaseAddr

private

Base address of mapped memory region.

Definition at line 36 of file TMapFile.h.

◆ fBrowseList

TList* TMapFile::fBrowseList

private

List of KeyMapFile objects.

Definition at line 42 of file TMapFile.h.

◆ fDirectory

TDirectory* TMapFile::fDirectory

private

Pointer to directory associated to this mapfile.

Definition at line 41 of file TMapFile.h.

◆ fFd

Int_t TMapFile::fFd

private

Descriptor of mapped file.

Definition at line 30 of file TMapFile.h.

◆ fFirst

TMapRec* TMapFile::fFirst

private

List of streamed objects is shared memory.

Definition at line 38 of file TMapFile.h.

◆ fGetting

TObject* TMapFile::fGetting

private

Don't deadlock in update mode, when from Get() Add() is called.

Definition at line 46 of file TMapFile.h.

◆ fgMapAddress

Long_t TMapFile::fgMapAddress = 0

staticprivate

Map to this address, set address via SetMapAddress()

Definition at line 51 of file TMapFile.h.

◆ fgMmallocDesc

void * TMapFile::fgMmallocDesc = 0

staticprivate

Used in Close() and operator delete()

Definition at line 52 of file TMapFile.h.

◆ fhSemaphore

ULong_t TMapFile::fhSemaphore

private

HANDLE of WIN32 Mutex object to implement semaphore.

Definition at line 45 of file TMapFile.h.

◆ fLast

TMapRec* TMapFile::fLast

private

Last object in list of shared objects.

Definition at line 39 of file TMapFile.h.

◆ fMmallocDesc

void* TMapFile::fMmallocDesc

private

Pointer to mmalloc descriptor.

Definition at line 35 of file TMapFile.h.

◆ fName

char* TMapFile::fName

private

Name of mapped file.

Definition at line 32 of file TMapFile.h.

◆ fOffset

Long_t TMapFile::fOffset

private

Offset in bytes for region mapped by reader.

Definition at line 40 of file TMapFile.h.

◆ fOption

char* TMapFile::fOption

private

Directory creation options.

Definition at line 34 of file TMapFile.h.

◆ fSemaphore

Int_t TMapFile::fSemaphore

private

Modification semaphore (or getpid() for WIN32)

Definition at line 44 of file TMapFile.h.

◆ fSize

Int_t TMapFile::fSize

private

Original start size of memory mapped region.

Definition at line 37 of file TMapFile.h.

◆ fSum2Buffer

Double_t TMapFile::fSum2Buffer

private

Sum of squares of buffer sizes of objects written so far.

Definition at line 49 of file TMapFile.h.

◆ fSumBuffer

Double_t TMapFile::fSumBuffer

private

Sum of buffer sizes of objects written sofar.

Definition at line 48 of file TMapFile.h.

◆ fTitle

char* TMapFile::fTitle

private

Title of mapped file.

Definition at line 33 of file TMapFile.h.

◆ fVersion

Int_t TMapFile::fVersion

private

ROOT version (or -1 for shadow map file)

Definition at line 31 of file TMapFile.h.

◆ fWritable

Bool_t TMapFile::fWritable

private

TRUE if mapped file opened in RDWR mode.

Definition at line 43 of file TMapFile.h.

◆ fWritten

Int_t TMapFile::fWritten

private

Number of objects written sofar.

Definition at line 47 of file TMapFile.h.

Libraries for TMapFile:

[legend]

The documentation for this class was generated from the following files:

io/io/inc/TMapFile.h
io/io/src/TMapFile.cxx

Public Types

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Private Attributes

Static Private Attributes

Friends

Additional Inherited Members

Member Enumeration Documentation

◆ anonymous enum

Constructor & Destructor Documentation

◆ TMapFile() [1/3]

◆ TMapFile() [2/3]

◆ TMapFile() [3/3]

◆ ~TMapFile()

Member Function Documentation

◆ AcquireSemaphore()

◆ Add()

◆ Browse()

◆ cd()

◆ Close()

◆ Create()

◆ CreateSemaphore()

◆ DeleteSemaphore()

◆ FindShadowMapFile()

◆ Get()

◆ GetBaseAddr()

◆ GetBestBuffer()

◆ GetBreakval()

◆ GetDirectory()

◆ GetFd()

◆ GetFirst()

◆ GetLast()

◆ GetMmallocDesc()

◆ GetName()

◆ GetOption()

◆ GetSize()

◆ GetTitle()

◆ InitDirectory()

◆ IsFolder()

◆ IsWritable()

◆ ls()

◆ MapToAddress()

◆ operator delete()

◆ operator new() [1/2]

◆ operator new() [2/2]

◆ operator new[]() [1/2]

◆ operator new[]() [2/2]

◆ operator=()

◆ OrgAddress()

◆ Print()

◆ ReleaseSemaphore()

◆ Remove() [1/4]

◆ Remove() [2/4]

◆ Remove() [3/4]

◆ Remove() [4/4]

◆ RemoveAll()

◆ SetMapAddress()

◆ SumBuffer()

◆ Update()

◆ WhichMapFile()

Friends And Related Symbol Documentation

◆ TMapRec

Member Data Documentation

◆ fBaseAddr

◆ fBrowseList

◆ fDirectory

◆ fFd

◆ fFirst

◆ fGetting

◆ fgMapAddress

◆ fgMmallocDesc

◆ fhSemaphore

◆ fLast

◆ fMmallocDesc

◆ fName

◆ fOffset

◆ fOption

◆ fSemaphore