Logo ROOT   6.10/09
Reference Guide
threadsh1.C File Reference

Detailed Description

Example of a simple script creating 3 threads.

This script can only be executed via ACliC .x threadsh1.C++.

#include "TCanvas.h"
#include "TFrame.h"
#include "TH1F.h"
#include "TRandom.h"
#include "TThread.h"
TCanvas *c[4];
TH1F *hpx[4];
TThread *t[5];
Bool_t finished;
void *handle(void *ptr)
{
long nr = (long) ptr;
Long64_t nfills = 25000000;
int upd = 50000;
char name[32];
sprintf(name,"hpx%ld",nr);
hpx[nr] = new TH1F(name,"This is the px distribution",100,-4,4);
hpx[nr]->SetFillColor(48);
Float_t px, py, pz;
gRandom->SetSeed();
for (Int_t i = 0; i < nfills; i++) {
gRandom->Rannor(px,py);
pz = px*px + py*py;
hpx[nr]->Fill(px);
if (i && (i%upd) == 0) {
if (i == upd) {
c[nr]->cd();
hpx[nr]->Draw();
}
if (c[nr]) c[nr]->Modified();
gSystem->Sleep(10);
}
}
return 0;
}
void *joiner(void *)
{
t[0]->Join();
t[1]->Join();
t[2]->Join();
t[3]->Join();
finished = kTRUE;
return 0;
}
void closed(Int_t id)
{
// kill the thread matching the canvas being closed
t[id]->Kill();
// and set the canvas pointer to 0
c[id] = 0;
}
void threadsh1()
{
finished = kFALSE;
//gDebug = 1;
c[0] = new TCanvas("c0","Dynamic Filling Example",100,20,400,300);
c[0]->SetFillColor(42);
c[0]->GetFrame()->SetFillColor(21);
c[0]->GetFrame()->SetBorderSize(6);
c[0]->GetFrame()->SetBorderMode(-1);
c[1] = new TCanvas("c1","Dynamic Filling Example",510,20,400,300);
c[1]->SetFillColor(42);
c[1]->GetFrame()->SetFillColor(21);
c[1]->GetFrame()->SetBorderSize(6);
c[1]->GetFrame()->SetBorderMode(-1);
c[2] = new TCanvas("c2","Dynamic Filling Example",100,350,400,300);
c[2]->SetFillColor(42);
c[2]->GetFrame()->SetFillColor(21);
c[2]->GetFrame()->SetBorderSize(6);
c[2]->GetFrame()->SetBorderMode(-1);
c[3] = new TCanvas("c3","Dynamic Filling Example",510,350,400,300);
c[3]->SetFillColor(42);
c[3]->GetFrame()->SetFillColor(21);
c[3]->GetFrame()->SetBorderSize(6);
c[3]->GetFrame()->SetBorderMode(-1);
// connect to the Closed() signal to kill the thread when a canvas is closed
c[0]->Connect("Closed()", 0, 0, "closed(Int_t=0)");
c[1]->Connect("Closed()", 0, 0, "closed(Int_t=1)");
c[2]->Connect("Closed()", 0, 0, "closed(Int_t=2)");
c[3]->Connect("Closed()", 0, 0, "closed(Int_t=3)");
printf("Starting Thread 0\n");
t[0] = new TThread("t0", handle, (void*) 0);
t[0]->Run();
printf("Starting Thread 1\n");
t[1] = new TThread("t1", handle, (void*) 1);
t[1]->Run();
printf("Starting Thread 2\n");
t[2] = new TThread("t2", handle, (void*) 2);
t[2]->Run();
printf("Starting Thread 3\n");
t[3] = new TThread("t3", handle, (void*) 3);
t[3]->Run();
printf("Starting Thread 4\n");
t[4] = new TThread("t4", joiner, (void*) 3);
t[4]->Run();
while (!finished) {
for (int i = 0; i < 4; i++) {
if (c[i] && c[i]->IsModified()) {
//printf("Update canvas %d\n", i);
c[i]->Update();
}
}
gSystem->Sleep(100);
}
t[4]->Join();
delete t[0];
delete t[1];
delete t[2];
delete t[3];
delete t[4];
}
Author
Victor Perevovchikov

Definition in file threadsh1.C.