Skip to main content

GDB



GDB is the standard debugger for Linux and Unix-like operating systems.

A good debugger is one of the most important tools in a programmer's toolkit. On a UNIX or Linux system, GDB (the GNU debugger) is a powerful and popular debugging tool; it lets you do whatever you like with your program running under GDB.
Should you read this?
You should... if you can relate to two or more of the following:

You have a general idea of programming with C or C++.
You put a lot of cout or printf statements in the code if something goes wrong.
You have used a debugger with an IDE, and are curious about how the command line works.
You've just moved to a Unix-like operating system and would like to know about the toolchain better.
A crash course on compiling with gcc (or g++)

Gcc is the de facto compiler in Linux or any other *nix system. It also has Windows ports but on Windows, you'll probably find the debugger in Visual Studio 'easier'.
Suppose you have a file called main.cpp containing your c++ code. You should compile it with the following command:

g++ main.cpp -o main

While this will work fine and produce an executable file called main, you also need to put a -g flag to tell the compiler that you may want to debug your program later.
So the final command turns into:

g++ main.cpp -g -Wall -Werror -o main

(If you're wondering what -Wall and -Werror are, you may find this page on GCC a useful read.)
Don't worry if it looks cumbersome, you'll get used to it! (If you've got multiple source files you should use a good build system like make or Scons.)


Popular posts from this blog

Putimage function in c

putimage function outputs a bit image onto the screen. Declaration:- void putimage(int left, int top, void *ptr, int op); putimage puts the bit image previously saved with getimage back onto the screen, with the upper left corner of the image placed at (left, top). ptr points to the area in memory where the source image is stored. The op argument specifies a operator that controls how the color for each destination pixel on screen is computed, based on pixel already on screen and the corresponding source pixel in memory. c smiling face animation This animation using c draws a smiling face which appears at random position on screen. See output below the code, it will help you in understanding the code easily. C programming code #include<graphics.h> #include<conio.h> #include<stdlib.h>   main() { int gd = DETECT, gm, area, temp1, temp2, left = 25, top = 75; void *p;   initgraph(&gd,&gm,"C:\\TC\\BGI");   setcolor(YELLOW)...
Read more

What are selection statements in C++ ? If and Switch

There are several statements that we can use in C++ programming that help in choosing a set of instructions for using the code depending upon an expression truth value.  What are Selection Statements in C++? As mentioned above there are several statements that we can use to choose a set of pre-defined instructions within a program in any section of the program as per the need. These are called selection statements in C++  In C++ Program there are two types of Selection statements  1. If  2. Switch  The If Statement of C++ To understand "if statement" let's look at an example.  Example - If you have 10 rupees then you can buy the chocolate.  Here, there is a condition in buying chocolate, if you have 10 rupees then only you can buy it.  This shows that the If is a condition which can be true or false, If it is false it won't be executed, in this example, if you don't have 10 rupees i.e. the condition is false you cant buy the chocolate.  So, I...
Read more

What are the characteristics of a good program in C++

The program should be written in a good style so that it is understandable to a reader. A good program is efficient in solving the given program.  Here are some of the characteristics of a good program : Effective and Efficient  User Friendly  Self-Documenting Code  Reliable  Portable  I.  Effective and Efficient The program produces correct results and works faster, taking into account of the memory constraints.  II.  User Friendly The user should not be concerned about inside the program, a program should work with the user by understandable messages and user work should be very low. The user should only be responsible to provide input the rest of the program should do.  III.  Self-Documenting Code A good program must be self-documented. The source code uses meaningful names for variables, subprograms and other constants.  IV.  Reliable The program must be able to handle unexpected situations like wrong data or no data,...
Read more