Skip to main content

How to use gdb in Ubuntu Terminal

Here's a practical, minimal guide for using GDB in Ubuntu terminal — from launching to setting breakpoints and navigating your code. 🧰 Step 1: Compile with Debug Symbols Use -g and disable optimizations ( -O0 preferred for debugging): bash Copy Edit g++ -g -O0 -o myprog myprog.cpp 🚀 Step 2: Launch GDB bash Copy Edit gdb ./myprog You'll see a (gdb) prompt. 🎯 Step 3: Set Breakpoints You can set breakpoints in three main ways : ✅ a. At a function gdb Copy Edit (gdb) break main ✅ b. At a specific file and line gdb Copy Edit (gdb) break myprog.cpp:42 ✅ c. At a method in a class gdb Copy Edit (gdb) break MyClass::doSomething If the symbol is mangled (C++), GDB usually demangles automatically, especially if compiled with -g . ▶️ Step 4: Run the Program gdb Copy Edit (gdb) run 🧭 Step 5: Navigate Command Meaning next or n Step over current line step or s Step into function call finish Run until current function returns continue or c Continue until...

C++ code to connect Postgres Database

/* At first install libpqxx in linux*/

#include <pqxx/pqxx>

using namespace std;
using namespace pqxx;

class GetDbConn
{
public:
    static connection *getPostgresDbConnection(const std::string& conStr)
    {
        pqxx::connection *c=new connection(conStr);
        return c;
    }
};

----------------

/*Code to call this connection is as follows

#include <pqxx/pqxx>
#include "getDbConn.h"

using namespace std;
using namespace pqxx;

class MyDb
{
public:
    static connection * getTradingNseConnection()
    {
        char const *conStr="dbname = <database_name> user = <user_name> password = <db_password> hostaddr = 127.0.0.1 port = 5432";
        pqxx::connection *con=GetDbConn::getPostgresDbConnection(conStr);
        if ((*con).is_open())
        {
            cout << "Opened database successfully: " << (*con).dbname() << endl;
            return con;
        }
        else
        {
            cout << "Can't open database" << endl;
            return NULL;
        }
    }
};

Comments

Popular posts from this blog

Ubuntu Notes: Set up autossh as systemd useful-reminder commands

 sudo vim /etc/systemd/system/permanentAutossh.service ======================================== [Unit] Description=Keeps a tunnel to myOciFreeNat open After=network-online.target [Service] User=<username> Environment="AUTOSSH_GATETIME=0" ExecStart=/usr/bin/autossh -M 0 -q -N -o "ServerAliveInterval 60" -o "ServerAliveCountMax 3" -L 4322:127.0.0.1:5432 -i /<ssh_private_key_file_absolute_path> <username>@<ip_address> -p 22 [Install] WantedBy=multi-user.target ======================================== sudo systemctl daemon-reload sudo systemctl enable permanentAutossh sudo systemctl start permanentAutossh ================== sudo systemctl daemon-reload sudo systemctl restart permanentAutossh sudo systemctl status permanentAutossh ====================== sudo systemctl stop permanentAutossh sudo systemctl disable permanentAutossh sudo rm /etc/systemd/system/permanentAutossh.service

syslog cpp programming: learning using chatGcp

  Introduction to Syslog C++ August 27, 2024 This conversation may reflect the link creator’s personalized data, which isn’t shared and can meaningfully change how the model responds. You said: I am new to syslog in cpp programming n just starting. Can you teach me ChatGPT said: ChatGPT Sure! syslog is a standard for logging system messages in Unix-like operating systems. It provides a way to send log messages to the system log, which can then be collected and analyzed by various tools. Here's a basic guide to get you started with syslog in C++: 1. Include the Necessary Header To use syslog , you need to include the syslog.h header: cpp Copy code # include <syslog.h> 2. Open the Connection to syslog Before sending log messages, you need to open a connection to the syslog system. This is typically done at the start of your program: cpp Copy code openlog ( "your_program_name" , LOG_PID | LOG_CONS, LOG_USER); "your_program_name" : A string representing ...

Ubuntu - C++ Notes: Install & update boost c++ library from git (may contain some error in process mentioned below)

 Boost C++ Library Installation from git in ubuntu: 1. create a directory named boost in your desired location and go to that directory mkdir boost;cd boost; 2. clone boost recursively from git using command git clone --recursive https://github.com/boostorg/boost.git 3. cd boost; sudo ./bootstrap.sh; 4. sudo ./b2; 5. sudo ./b2 install; DONE! --------------------------- Boost C++ Library Update Verson from git in Ubuntu: 1. go to gitDownloads/boost directory cd gitDownloads/boost; 2. git pull; 3. git submodule update --recursive; 4. cd boost; sudo ./bootstrap.sh; 5. sudo ./b2; 6. sudo ./b2 install; DONE!