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Reference Guide
hserv2.C File Reference

Detailed Description

This script shows how to make a simple iterative server that can accept connections while handling currently open connections.

Compare this script to hserv.C that blocks on accept. In this script a server socket is created and added to a monitor. A monitor object is used to monitor connection requests on the server socket. After accepting the connection the new socket is added to the monitor and immediately ready for use. Once two connections are accepted the server socket is removed from the monitor and closed. The monitor continues monitoring the sockets.

To run this demo do the following:

  • Open three windows
  • Start ROOT in all three windows
  • Execute in the first window: .x hserv2.C
  • Execute in the second and third windows: .x hclient.C
{
// Create canvas and pads to display the histograms
TCanvas *c1 = new TCanvas("c1","The Ntuple canvas",200,10,700,780);
TPad *pad1 = new TPad("pad1","This is pad1",0.02,0.52,0.98,0.98,21);
TPad *pad2 = new TPad("pad2","This is pad2",0.02,0.02,0.98,0.48,21);
pad1->Draw();
pad2->Draw();
// Open a server socket looking for connections on a named service or
// on a specified port.
//TServerSocket *ss = new TServerSocket("rootserv", kTRUE);
TServerSocket *ss = new TServerSocket(9090, kTRUE);
TMonitor *mon = new TMonitor;
mon->Add(ss);
TSocket *s0 = 0, *s1 = 0;
while (1) {
TMessage *mess;
s = mon->Select();
if (s->IsA() == TServerSocket::Class()) {
if (!s0) {
s0 = ((TServerSocket *)s)->Accept();
s0->Send("go 0");
mon->Add(s0);
} else if (!s1) {
s1 = ((TServerSocket *)s)->Accept();
s1->Send("go 1");
mon->Add(s1);
} else
printf("only accept two client connections\n");
if (s0 && s1) {
mon->Remove(ss);
ss->Close();
}
continue;
}
s->Recv(mess);
if (mess->What() == kMESS_STRING) {
char str[64];
mess->ReadString(str, 64);
printf("Client %d: %s\n", s==s0 ? 0 : 1, str);
mon->Remove(s);
if (mon->GetActive() == 0) {
printf("No more active clients... stopping\n");
break;
}
} else if (mess->What() == kMESS_OBJECT) {
//printf("got object of class: %s\n", mess->GetClass()->GetName());
TH1 *h = (TH1 *)mess->ReadObject(mess->GetClass());
if (h) {
if (s == s0)
pad1->cd();
else
pad2->cd();
h->Print();
h->DrawCopy(); //draw a copy of the histogram, not the histo itself
c1->Modified();
c1->Update();
delete h; // delete histogram
}
} else {
printf("*** Unexpected message ***\n");
}
delete mess;
}
printf("Client 0: bytes recv = %d, bytes sent = %d\n", s0->GetBytesRecv(),
s0->GetBytesSent());
printf("Client 1: bytes recv = %d, bytes sent = %d\n", s1->GetBytesRecv(),
s1->GetBytesSent());
// Close the socket.
s0->Close();
s1->Close();
}
void Class()
Definition: Class.C:29
@ kMESS_STRING
Definition: MessageTypes.h:34
@ kMESS_OBJECT
Definition: MessageTypes.h:35
#define s0(x)
Definition: RSha256.hxx:90
#define s1(x)
Definition: RSha256.hxx:91
#define h(i)
Definition: RSha256.hxx:106
const Bool_t kTRUE
Definition: RtypesCore.h:87
TObject * ReadObject(const TClass *cl) override
Read object from I/O buffer.
char * ReadString(char *s, Int_t max) override
Read string from I/O buffer.
The Canvas class.
Definition: TCanvas.h:31
The TH1 histogram class.
Definition: TH1.h:56
UInt_t What() const
Definition: TMessage.h:75
TClass * GetClass() const
Definition: TMessage.h:71
TSocket * Select()
Return pointer to socket for which an event is waiting.
Definition: TMonitor.cxx:322
virtual void Add(TSocket *sock, Int_t interest=kRead)
Add socket to the monitor's active list.
Definition: TMonitor.cxx:168
Int_t GetActive(Long_t timeout=-1) const
Return number of sockets in the active list.
Definition: TMonitor.cxx:438
virtual void Remove(TSocket *sock)
Remove a socket from the monitor.
Definition: TMonitor.cxx:214
The most important graphics class in the ROOT system.
Definition: TPad.h:29
virtual void Draw(Option_t *option="")
Draw Pad in Current pad (re-parent pad if necessary).
Definition: TPad.cxx:1282
TVirtualPad * cd(Int_t subpadnumber=0)
Set Current pad.
Definition: TPad.cxx:591
virtual void Close(Option_t *opt="")
Close the socket.
Definition: TSocket.cxx:388
return c1
Definition: legend1.C:41
static constexpr double s
Author
Fons Rademakers

Definition in file hserv2.C.