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NOTE: For Ruby 1.9 installation instructions, please see:
= ruby-debug
== Overview
ruby-debug is a fast implementation of the standard debugger debug.rb.
The faster execution speed is achieved by utilizing a new hook in the
Ruby C API.
== Requirements
ruby-debug requires Ruby 1.8.4 or higher.
Unless you get the packages as a binary (Microsoft Windows binaries
are sometimes available), you'll need a C compiler and Ruby
development headers, and a Make program so the extension in
ruby-debug-base can be compiled when it is installed.
To install on Microsoft Windows, unless you run under cygwin or mingw
you'll need Microsoft Visual C++ 6.0 also known as VC6.
suggests why.
== Install
ruby-debug is provided as a RubyGem. To install:
<tt>gem install ruby-debug</tt>
This should also pull in <tt>ruby-debug-base</tt> as a dependency.
(If you install ruby-debug-base explicitly, you can add in the <tt>--test</tt>
option after "install" to have the regression test run before
For Emacs support and the Reference Manual, get
<tt>ruby-debug-extra</tt>. This is not a RubyGem, you'll need a Make
program and a POSIX shell. With this installed, run:
sh ./configure
make test # optional, but a good idea
sudo make install
==== Install on MS Windows
Compiling under cygwin or mingw works like it does on Unix.
* Have Microsoft Visual C++ 6.0 (VC6) installed - exactly that version.
* Set the appropriate environment variables.
* run `nmake'.
* Copy to `win32'.
* Go to the ruby_debug root.
* rake win32_gem
* The file is in named `rdebug-debug-base-0.10.0-mswin32.gem'.
== Usage
There are two ways of running ruby-debug.
=== rdebug executable:
$ rdebug <your-script>
When you start your script this way, the debugger will stop at
the first line of code in the script file. So you will be able
to set up your breakpoints.
=== ruby-debug API
The second way is to use the ruby-debug API to interrupt your
code execution at run time.
require 'ruby-debug' ; Debugger.start
def your_method
require 'ruby-debug' ;
Debugger.start do
When Kernel#debugger method is executed, the debugger is activated
and you will be able to inspect and step through your code.
== Performance
The <tt>debug.rb</tt> script that comes with the standard Ruby library uses
<tt>Kernel#set_trace_func</tt> API. Implementing the debugger in pure Ruby has
a negative impact on the speed of your program execution. This is
because the Ruby interpreter creates a Binding object each trace call,
even though it is not being used most of the time. ruby-debug moves
most of the functionality for Binding access and for breakpoint
testing to a native extension. Because this code is in C and because
and can be selectively enabled or disabled, the overhead in running
your program can be minimized.
== License
See LICENSE for license information.