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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;
TSocket *s;
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();
}
@ kMESS_STRING
@ kMESS_OBJECT
#define s0(x)
Definition RSha256.hxx:90
#define s1(x)
Definition RSha256.hxx:91
#define h(i)
Definition RSha256.hxx:106
constexpr Bool_t kTRUE
Definition RtypesCore.h:100
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:23
TH1 is the base class of all histogram classes in ROOT.
Definition TH1.h:58
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:28
TVirtualPad * cd(Int_t subpadnumber=0) override
Set Current pad.
Definition TPad.cxx:597
void Draw(Option_t *option="") override
Draw Pad in Current pad (re-parent pad if necessary).
Definition TPad.cxx:1268
static TClass * Class()
virtual Int_t Recv(TMessage *&mess)
Receive a TMessage object.
Definition TSocket.cxx:818
virtual void Close(Option_t *opt="")
Close the socket.
Definition TSocket.cxx:389
TClass * IsA() const override
Definition TSocket.h:171
virtual Int_t Send(const TMessage &mess)
Send a TMessage object.
Definition TSocket.cxx:522
void Print(const char *filename="") const override=0
This method must be overridden when a class wants to print itself.
return c1
Definition legend1.C:41
Author
Fons Rademakers

Definition in file hserv2.C.