20100712-OTcl Command -- Getting Started

NS2: OTcl Command – Getting Started by Teerawat Issariyakul http://www.ns2ultimate.com July 2010 http://www.ns2ultimate.com

Outline
Introduction
Motivation
What we would like to do
OTcl Command
http://www.ns2ultimate.com

Introduction
This is a series on how NS2 binds C++ and OTcl together. This is the second topic of the series:
Why Two Languages?
Binding C++ and OTcl classes
Variable binding
OTcl command: Invoking C++ statements from the OTcl domain
Eval and result: Invoking OTcl statements from the C++ domain
Object binding and object construction process.

Motivation
OTcl is the place where users do the programming
Sometimes, users need to call C++ function
http://www.ns2ultimate.com MyObject programmer C++ MyOTclObject OTcl binding function binding class name delay_ show_delay(){ show “delay_” on the screen } show-delay

What we would like to do http://www.ns2ultimate.com
C++:
class = MyObject (see above)
variable = delay_
function: show_delay()
OTcl:
class = MyOTclObject (see above)
variable = none
OTcl command: show-delay
Binding class name [see here and here ]
MyObject C++ MyOTclObject OTcl binding function binding class name (see above) delay_ show_delay(){ show “delay_” on the screen } show-delay

OTcl Command: Introduction
Can be invoked from the OTcl domain ( show-delay )
Is bound to an OTcl object ( object )
Execute C++ domain ( show_delay() )

OTcl Command: C++ files
In the following, I will use files in the previous post: otcl.cc, otcl.h, otcl.tcl
Add a C++ variable delay_ to class MyObject
http://www.ns2ultimate.com class MyObject : public TclObject { public: MyObject(); virtual ~MyObject(){}; protected: int count_; double delay_; double speed_; double virtual_time_; int is_running_; int command(int argc, const char*const* argv); }; otcl.h

OTcl Command: C++ files
In the following, I will use files in the previous post: otcl.cc, otcl.h, otcl.tcl
Add a C++ variable delay_ to class MyObject
Constructor: Set the initial value of delay_ to be 7.7
Do not bind the variable
Next step to use OTcl command to show the value of the variable delay_ on the screen
http://www.ns2ultimate.com MyObject::MyObject() { delay_ = 7.7; } otcl.cc

OTcl Command: Definition
Define within C++ class (e.g. MyObject )
Define by function “ command(…) ”
Example: Insert the following into the file otcl.cc
Do not forget to add a C++ variable delay_ to class MyObject
http://www.ns2ultimate.com int MyObject::command(int argc, const char*const* argv) { if (argc==2) { if (strcmp(argv[1], "show-delay") == 0) { printf("Delay is %g ", delay_); return (TCL_OK); } } return TclObject::command(argc, argv); }; OTcl command name what this OTcl command do

Summary of Key Steps
Use files otcl.cc and otcl.h in the previous post
Add the details as stated earlier
run “ make ” to incorporate C++ changes in to NS2 [see detail here ]
Create file otcl.tcl for testing
4.1 Create an OTcl object object
4.2 Invoke the OTcl command “show-delay” associated with object
4.4 Change the C++ constructor: set delay_ to be 9.9
4.5 Repeat 4.2 and 4.3

OTcl Command: Invocation
File otcl.tcl
Run the file otcl.tcl
http://www.ns2ultimate.com set ns [new Simulator] set obj [new MyOTclObject ] $obj show-delay

OTcl Command: Invocation
Modify the constructor
Run the file otcl.tcl again
http://www.ns2ultimate.com MyObject::MyObject() { delay_ = 9.9; }

For more information about NS 2 Please see this book from Springer T. Issaraiyakul and E. Hossain, “Introduction to Network Simulator NS2”, Springer 2009 http://www.ns2ultimate.com

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20100712-OTcl Command -- Getting Started

by Teerawat Issariyakul on Jul 11, 2010

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20100712-OTcl Command -- Getting Started — Presentation Transcript