## Why modify gdb?

Using the original gdb to print variables in a running process requires first attaching, and attaching will interrupt the running process.

This can cause some problems, such as:
* Causing the process to run differently, making the problem unable to reproduce.
* May affect related business and is typically not allowed in production environments.

In fact, it is not necessary to attach to a process in order to obtain the value of global variables. By reading the `/proc/PID/mem` file, it is possible to obtain sufficient information.

Therefore, I have modified gdb so that it can print the value of global variables without interrupting the process.

## How to use the new feature?

Just execute `gdb -m <PID>`.
This operation will not attach the process. You can use the `p` and `x` commands to print global variables.

When specifying the `-m` parameter, modification of variable values (`set var = value`) and `attach` and `run` commands are prohibited to avoid misoperations.

If you really want to modify global variable values, you can use the `-M` parameter, but it is not recommended in a production environment.


The following is the original README.

---

		   README for GNU development tools

This directory contains various GNU compilers, assemblers, linkers, 
debuggers, etc., plus their support routines, definitions, and documentation.

If you are receiving this as part of a GDB release, see the file gdb/README.
If with a binutils release, see binutils/README;  if with a libg++ release,
see libg++/README, etc.  That'll give you info about this
package -- supported targets, how to use it, how to report bugs, etc.

It is now possible to automatically configure and build a variety of
tools with one command.  To build all of the tools contained herein,
run the ``configure'' script here, e.g.:

	./configure 
	make

To install them (by default in /usr/local/bin, /usr/local/lib, etc),
then do:
	make install

(If the configure script can't determine your type of computer, give it
the name as an argument, for instance ``./configure sun4''.  You can
use the script ``config.sub'' to test whether a name is recognized; if
it is, config.sub translates it to a triplet specifying CPU, vendor,
and OS.)

If you have more than one compiler on your system, it is often best to
explicitly set CC in the environment before running configure, and to
also set CC when running make.  For example (assuming sh/bash/ksh):

	CC=gcc ./configure
	make

A similar example using csh:

	setenv CC gcc
	./configure
	make

Much of the code and documentation enclosed is copyright by
the Free Software Foundation, Inc.  See the file COPYING or
COPYING.LIB in the various directories, for a description of the
GNU General Public License terms under which you can copy the files.

REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info
on where and how to report problems.