mcr/shared_memories/Producer_Diego.C

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/file.h>
#include <fcntl.h>


#include <Riostream.h>
#include <stdio.h>
#include "TH1F.h"
#include "TH2F.h"
#include "TProfile.h"
#include "TRandom.h"
#include "TMapFile.h"
#include "TSystem.h"
#include "TString.h"

/*
void HandleLockShFile(const Char_t *fnam,Bool_t lock){
  // lock file 'fnam' if 'lock' is true
  Int_t Fdescr = 0;
  cout << endl << " -- -- -- " << endl;
  
  if(lock){
    cout << " -> Locking shared file \"" << fnam << "\"" << endl;
    Fdescr = open(fnam,O_CREAT);
    Int_t Flock = flock(Fdescr,LOCK_SH);
    cout << "     lock output: " << Flock << endl;
  }
  else{
    cout << " -> Unlocking shared file \"" << fnam << "\"" << endl;
    Fdescr = open(fnam,O_RDONLY);
    Int_t Funlock = flock(Fdescr,LOCK_UN);
    cout << "     unlock output: " << Funlock << endl;
  }
    cout << "      shared file descriptor: " << Fdescr << endl; 

    Int_t FileDescr_close = close(Fdescr);
    cout << "File descriptor \"" << Fdescr << "\" closed (close returned: " << FileDescr_close << ")" << endl;
}
*/

void HandleConsumerActions(const Char_t *sh_msg_file, Bool_t allow){
  // the content of the shared text file 'shared_msg.txt' is
  // used by the consumer(s).
  // Consumer(s) can act (open, read...map-files) if 'allow' is true

  TString com = TString("echo ");
  Int_t size1 = com.Sizeof()-1;
  if(allow) com+="\"go\" > ";
  else com+="\"wait\" > ";
  com+=sh_msg_file;
  gSystem->Exec(com.Data());

  com.Resize(size1);
  com+="\"\" >> ";
  com+=sh_msg_file;
  gSystem->Exec(com.Data());

}

void Producer_Diego(){

  TString mnam = TString(gSystem->Getenv("FND_SHR"));
  mnam+="/hsimple.map";
  TString msgnam = TString(gSystem->Getenv("FND_SHR"));
  msgnam+="/shared_msg.txt";

  TString comm1 = TString("touch ");
  comm1+=msgnam.Data();
  gSystem->Exec(comm1.Data());

  HandleConsumerActions(msgnam.Data(),0); // deny consumer(s) actions
  //  TMapFile::SetMapAddress(0x40028000);
  // --- remove mapped file
  TString command_rm = TString("rm -f ");
  command_rm+=mnam.Data();
  gSystem->Exec(command_rm.Data());
  // --- recreate mapped file
  gSystem->Sleep(300); 
  TMapFile *mfile = TMapFile::Create(mnam.Data(),"RECREATE", 100000,"Demo memory mapped file");
  gSystem->Sleep(300); 
  
  cout << "mfile is: " << mfile << endl;
  mfile->Print();

  TH1F *h1    = new TH1F("h1","Histogram 1",100,-4,4);
  h1->SetFillColor(48);
  mfile->Update();
  HandleConsumerActions(msgnam.Data(),1); // allow consumer(s) actions

  mfile->ls();
  
  
  TString command_touch = TString("touch ");
  command_touch+=mnam.Data();
  int ev = 0;
  while (1) {
    cout << "Filling" << endl;
    h1->Fill(3);
    mfile->Update();
    gSystem->Exec(command_touch.Data());
    gSystem->ProcessEvents();
    mfile->ls();
    Char_t a[10];
    cout << "press any key to continue (fill and update)" << endl;
    cin >> a;
    if(!strcmp(a,"q")) break;
    ev++;
  }
  HandleConsumerActions(msgnam.Data(),0); // deny consumer(s) actions
  cout << "Closing mapfile" << endl; 
  mfile->Close();
  cout << "done: setting pointer to zero" << endl; 
  mfile = 0;
  cout << "done." << endl; 

}

---