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TExec Class Reference

TExec is a utility class that can be used to execute a C++ command when some event happens in a pad.

The command in turn can invoke a C++ macro to paint graphics objects at positions depending on the histogram or graph contents.

Case 1:

The TExec object is in the list of pad primitives (after exec.Draw()). When the pad is drawn, the TExec::Paint function is called. This function will execute the specified command. The following example uses the services of the class Aclock created in $ROOTSYS/test/Aclock.cxx. This examples uses a TTimer to redraw a pad at regular intervals (clock). When the clock is updated, a string with the current date&time is drawn.

Aclock ck(400);
TDatime dt;
TText t(.5,.3,"t");
TExec ex("ex","dt.Set();t.SetTitle(dt.AsString())");
R__EXTERN TSystem * gSystem
Definition TSystem.h:559
#define gPad
This class stores the date and time with a precision of one second in an unsigned 32 bit word (950130...
Definition TDatime.h:37
TExec is a utility class that can be used to execute a C++ command when some event happens in a pad.
Definition TExec.h:28
virtual int Load(const char *module, const char *entry="", Bool_t system=kFALSE)
Load a shared library.
Definition TSystem.cxx:1855
Base class for several text objects.
Definition TText.h:22
Double_t ex[n]
Definition legend1.C:17

Case 2:

The TExec object may be added to the list of functions of a TH1 or TGraph object via hist->GetListOfFunctions()->Add(exec). When the histogram (or graph) is drawn, the TExec will be executed. If the histogram is made persistent on a file, the TExec object is also saved with the histogram. When redrawing the histogram in a new session, the TExec will be executed.


Assume an histogram TH1F *h already filled.

TExec *ex1 = new TExec("ex1","DoSomething()");
TExec *ex2 = new TExec("ex2",".x macro.C");
#define h(i)
Definition RSha256.hxx:106
Exec default constructor.
Definition TExec.cxx:106

When the Paint function for the histogram will be called, the "DoSomething" function will be called (interpreted or compiled) and also the macro.C.

Case 3:

A TExec object is automatically generated when invoking TPad::AddExec. Each pad contains a TList of TExecs (0, 1 or more). When a mouse event (motion, click, etc) happens, the pad object executes sequentially this list of TExecs. In the code (interpreted or compiled) executed by the TExec referenced command, one can call the pad service functions such as TPad::GetEvent, TPad::GetEventX, TPad::GetEventY to find which type of event and the X,Y position of the mouse. By default, the list of TExecs is executed. This can be disabled via the canvas menu "Option". See $ROOTSYS/tutorials/hist/exec2.C for an example.

Root > TFile f("hsimple.root");
Root > hpxpy.Draw();
Root > c1.AddExec("ex2",".x exec2.C");
#define f(i)
Definition RSha256.hxx:104
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition TFile.h:54
return c1
Definition legend1.C:41

When moving the mouse in the canvas, a second canvas shows the projection along X of the bin corresponding to the Y position of the mouse. The resulting histogram is fitted with a gaussian. A "dynamic" line shows the current bin position in Y. This more elaborated example can be used as a starting point to develop more powerful interactive applications exploiting CINT as a development engine.

The 3 options above can be combined.

Definition at line 28 of file TExec.h.

Public Member Functions

 TExec ()
 Exec default constructor.
 TExec (const char *name, const char *command)
 Exec normal constructor.
 TExec (const TExec &text)
 Copy constructor.
virtual ~TExec ()
 Exec default destructor.
virtual void Exec (const char *command="")
 Execute the command referenced by this object.
virtual void Paint (Option_t *option="")
 Execute the command referenced by this object.
virtual void SavePrimitive (std::ostream &out, Option_t *option="")
 Save primitive as a C++ statement(s) on output stream out.
virtual void SetAction (const char *action)
- Public Member Functions inherited from TNamed
 TNamed ()
 TNamed (const char *name, const char *title)
 TNamed (const TNamed &named)
 TNamed copy ctor.
 TNamed (const TString &name, const TString &title)
virtual ~TNamed ()
 TNamed destructor.
virtual void Clear (Option_t *option="")
 Set name and title to empty strings ("").
virtual TObjectClone (const char *newname="") const
 Make a clone of an object using the Streamer facility.
virtual Int_t Compare (const TObject *obj) const
 Compare two TNamed objects.
virtual void Copy (TObject &named) const
 Copy this to obj.
virtual void FillBuffer (char *&buffer)
 Encode TNamed into output buffer.
virtual const char * GetName () const
 Returns name of object.
virtual const char * GetTitle () const
 Returns title of object.
virtual ULong_t Hash () const
 Return hash value for this object.
virtual Bool_t IsSortable () const
virtual void ls (Option_t *option="") const
 List TNamed name and title.
TNamedoperator= (const TNamed &rhs)
 TNamed assignment operator.
virtual void Print (Option_t *option="") const
 Print TNamed name and title.
virtual void SetName (const char *name)
 Set the name of the TNamed.
virtual void SetNameTitle (const char *name, const char *title)
 Set all the TNamed parameters (name and title).
virtual void SetTitle (const char *title="")
 Set the title of the TNamed.
virtual Int_t Sizeof () const
 Return size of the TNamed part of the TObject.
- 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.
virtual void Browse (TBrowser *b)
 Browse object. May be overridden for another default action.
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 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 TObjectDrawClone (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 TObjectFindObject (const char *name) const
 Must be redefined in derived classes.
virtual TObjectFindObject (const TObject *obj) const
 Must be redefined in derived classes.
virtual Option_tGetDrawOption () 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 Option_tGetOption () const
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.
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)
Bool_t IsDestructed () const
virtual Bool_t IsEqual (const TObject *obj) const
 Default equal comparison (objects are equal if they have the same address in memory).
virtual Bool_t IsFolder () const
 Returns kTRUE in case object contains browsable objects (like containers or lists of other objects).
R__ALWAYS_INLINE Bool_t IsOnHeap () 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 [].
voidoperator new (size_t sz)
voidoperator new (size_t sz, void *vp)
voidoperator new[] (size_t sz)
voidoperator new[] (size_t sz, void *vp)
TObjectoperator= (const TObject &rhs)
 TObject assignment operator.
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.
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.

Additional Inherited Members

- 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)
- Static Public Member Functions inherited from TObject
static Longptr_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 Types inherited from TObject
enum  { kOnlyPrepStep = BIT(3) }
- 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 ()
- Protected Attributes inherited from TNamed
TString fName
TString fTitle

#include <TExec.h>

Inheritance diagram for TExec:

Constructor & Destructor Documentation

◆ TExec() [1/3]

TExec::TExec ( )

Exec default constructor.

Definition at line 106 of file TExec.cxx.

◆ TExec() [2/3]

TExec::TExec ( const char *  name,
const char *  command 

Exec normal constructor.

Definition at line 114 of file TExec.cxx.

◆ TExec() [3/3]

TExec::TExec ( const TExec text)

Copy constructor.

Definition at line 128 of file TExec.cxx.

◆ ~TExec()

TExec::~TExec ( )

Exec default destructor.

Definition at line 121 of file TExec.cxx.

Member Function Documentation

◆ Exec()

void TExec::Exec ( const char *  command = "")

Execute the command referenced by this object.

if command is given, this command is executed otherwise the default command of the object is executed

if the default command (in the exec title) is empty, an attempt is made to execute the exec name if it contains a "." or a "(", otherwise the command ".x execname.C" is executed. The function returns the result of the user function/script.

Definition at line 144 of file TExec.cxx.

◆ Paint()

void TExec::Paint ( Option_t option = "")

Execute the command referenced by this object.

Reimplemented from TObject.

Definition at line 162 of file TExec.cxx.

◆ SavePrimitive()

void TExec::SavePrimitive ( std::ostream &  out,
Option_t option = "" 

Save primitive as a C++ statement(s) on output stream out.

Reimplemented from TObject.

Definition at line 170 of file TExec.cxx.

◆ SetAction()

virtual void TExec::SetAction ( const char *  action)

Definition at line 39 of file TExec.h.

  • core/base/inc/TExec.h
  • core/base/src/TExec.cxx