Writing documentations / comments in C/C++ in emacs/vim (chatGpt replies)

Q: In emacs/vim I writing c/cpp code n using lsp -clangd as auto complete. Now how to write documentations for my Fns so that when I hover over that Fn used somewhere else, I can see documentations eg say Fn multiply

int multiply(const int &a,const int &b){

return a*b;

}

...

...

int main(){

int a=2,b=3;

int c=multiply(a,b);

return 0;

}

I wn to wirte documentatiosn for multiply fn so that whenever I hover over multiply in main fn it show docs. How to do?

ChatGpt: To write documentation for your functions in C/C++ that will be displayed when you hover over the function in Emacs/Vim with `lsp-clangd`, you can use Doxygen-style comments. Here's how you can do it:


1. **Doxygen Comment Format:**

   Write your documentation using Doxygen-style comments above the function definition. These comments can include descriptions of the function, its parameters, and the return value.


2. **Example Documentation:**

   Here’s how you can document the `multiply` function:


   ```cpp

   /**

    * @brief Multiplies two integers.

    *

    * This function takes two integers by reference and returns their product.

    *

    * @param a The first integer to multiply.

    * @param b The second integer to multiply.

    * @return The product of the two integers.

    */

   int multiply(const int &a, const int &b) {

       return a * b;

   }

   ```


3. **Hover Documentation:**

   When you hover over the `multiply` function in `main`, `lsp-clangd` will display the above documentation.


4. **Enabling Documentation in `lsp-clangd`:**

   Make sure that your `clangd` setup is configured to show hover documentation. This is typically enabled by default in `lsp-mode`, but you can customize the behavior by configuring `lsp-ui-doc` or other relevant settings.


This approach will allow you to document your functions in a way that is compatible with both Emacs and Vim when using `lsp-clangd`.

Q: you said Doxygen-style comments. Any other style available (some more styles to write comments)??

chatGpt: Yes, while Doxygen-style comments are the most common and widely supported for C/C++ documentation, there are other styles you can use to write comments that might be recognized by different tools or conventions. Here are a few:


### 1. **Doxygen-Style Comments**

   - **Syntax:** `/** ... */`

   - **Usage:** Recognized by Doxygen, it’s a common way to document C/C++ code and integrates well with `clangd`.

   - **Example:**

     ```cpp

     /**

      * @brief Adds two integers.

      * @param x The first integer.

      * @param y The second integer.

      * @return The sum of x and y.

      */

     int add(int x, int y) {

         return x + y;

     }

     ```


### 2. **Javadoc-Style Comments**

   - **Syntax:** `/** ... */`

   - **Usage:** Similar to Doxygen but originates from Java. It can also be used in C/C++ with minor differences in tags.

   - **Example:**

     ```cpp

     /**

      * Adds two integers.

      * @param x The first integer.

      * @param y The second integer.

      * @return The sum of x and y.

      */

     int add(int x, int y) {

         return x + y;

     }

     ```


### 3. **Qt-Style Comments**

   - **Syntax:** `/*! ... */`

   - **Usage:** Qt uses this style in its documentation. It’s compatible with Doxygen but with slight differences in emphasis.

   - **Example:**

     ```cpp

     /*!

      * Adds two integers.

      * \param x The first integer.

      * \param y The second integer.

      * \return The sum of x and y.

      */

     int add(int x, int y) {

         return x + y;

     }

     ```


### 4. **Single-Line Comments**

   - **Syntax:** `///`

   - **Usage:** Used for brief documentation of functions or variables. This style is often used in C# and C++, and is supported by Doxygen.

   - **Example:**

     ```cpp

     /// Adds two integers and returns the result.

     /// @param x The first integer.

     /// @param y The second integer.

     /// @return The sum of x and y.

     int add(int x, int y) {

         return x + y;

     }

     ```


### 5. **Multiline Single-Line Comments**

   - **Syntax:** `///`

   - **Usage:** Allows you to write documentation in a compact way across multiple lines.

   - **Example:**

     ```cpp

     /// Adds two integers.

     /// This function takes two integers as input

     /// and returns their sum.

     /// @param x The first integer.

     /// @param y The second integer.

     /// @return The sum of x and y.

     int add(int x, int y) {

         return x + y;

     }

     ```


### 6. **In-line Comments**

   - **Syntax:** `// ...`

   - **Usage:** Used for very brief comments, though not typically used for documentation that tools like `clangd` or Doxygen would parse for hover information.

   - **Example:**

     ```cpp

     int add(int x, int y) {

         // This function adds two integers and returns the result.

         return x + y;

     }

     ```


### 7. **Plain Text Block Comments**

   - **Syntax:** `/* ... */`

   - **Usage:** General purpose and not usually parsed by documentation tools, but can be used for internal notes or explanations.

   - **Example:**

     ```cpp

     /* Adds two integers and returns the result. */

     int add(int x, int y) {

         return x + y;

     }

     ```


### Summary

- **Doxygen** and **Javadoc-style** comments are most popular for integration with tools that generate documentation and work well with `clangd`.

- **Qt-Style** and **single-line comments** are alternative methods that may be preferred based on project or organization standards.

- You can choose the style that fits your team's practices or the tools you plan to use for generating documentation.

How to Paste photo in pdf file at specific postion (using gimp)

Pdf viewer only allows to view files, but not to edit them say if you fill up pdf or paste photo in photo box it won't be possible

Suppose required to paste photo in photo box located in pdf file say in pg 2.

For this split pdf in pages -> import pf2.pdff in gimp -> open photo as layer in gimp

-> GIMP_menuBar {Tools > Transform Tools > Scale}->resize photo to required size -> click scale

-> Move photo do desired position using Move tool

->  [ crop photo if necessary, do adjustments needed in photo as requried]

-> Rt click on photo layer -> Merge_Down

-> File export as pdf

Now exported file will be the reqd pdf pg2 as needed

Merge pdf pages back using pdfunite

$pdfunite pg1.pdf pg2.pdf ... pgn.pdf output.pdf

DONE!

Uninstall package in Ubuntu 22 installed via apt

sudo apt-get remove <packageName>;

sudo apt-get purge <packageName>;

sudo apt-get autoremove;

sudo apt-get clean

How to configure .dir-locals.el file for emacs (for c/c++ project)?

 M-x add-dir-local-variable RET

Mode or subdirectory (default ....): nil RET

Add directory local variable: eval RET

Add eval with expression: (progn (company-mode t)(flycheck-mode t)) RET

Above will automatically turn on company-mode & flycheck-mode for the project files.

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

M-x add-dir-local-variable RET

Mode or subdirectory (default ....): c++-mode RET

Add directory local variable: flycheck-clang-language-standard RET

Add eval with expression: "c++20"

Similary add other variables so that final .dir-locals.el file looks like below:

;;; Directory Local Variables            -*- no-byte-compile: t -*-
;;; For more information see (info "(emacs) Directory Variables")

((nil . ((eval . (progn
   (company-mode t)
   (flycheck-mode t)))))

 (c++-mode . ((flycheck-clang-language-standard . "c++20")
     (flycheck-clang-include-path . ("/usr/include/postgresql"))
      (flycheck-gcc-include-path . ("/usr/include/postgresql")))))

=============
DONE!

Common Git Commands (chat gpt ans)

Here are some common Git commands to help you manage your repository, including committing changes, pushing to a remote repository, and more:

Basic Git Workflow

Initial Setup

  1. Initialize a New Git Repository:

     git init
    
  2. Clone an Existing Repository:

     git clone <repository_url>
    

Staging and Committing Changes

  1. Check the Status of Your Repository:

     git status
    
  2. Stage Changes:

    • Stage all changes:
        git add .
      
    • Stage specific files:
        git add <file1> <file2>
      
  3. Commit Changes:

     git commit -m "Your commit message"
    

Working with Remote Repositories

  1. Add a Remote Repository:

     git remote add origin <repository_url>
    
  2. Push Changes to a Remote Repository:

    • Push to the master branch (or main branch):
        git push -u origin master
      
    • Push to a specific branch:
        git push -u origin <branch_name>
      
  3. Pull Changes from a Remote Repository:

     git pull origin <branch_name>
    

Branching and Merging

  1. Create a New Branch:

     git branch <new_branch_name>
    
  2. Switch to a Different Branch:

    git checkout <branch_name>
    
  3. Create and Switch to a New Branch:

    git checkout -b <new_branch_name>
    
  4. Merge a Branch into the Current Branch:

    git merge <branch_name>
    

Viewing History

  1. View Commit History:

    git log
    
  2. View a Simplified Commit History:

    git log --oneline
    

Undoing Changes

  1. Unstage Changes:

    git reset <file>
    
  2. Undo Local Changes to a File:

    git checkout -- <file>
    
  3. Revert to a Previous Commit:

    git revert <commit_id>
    
  4. Reset to a Previous Commit:

    • Soft reset (keeps changes in the working directory):
        git reset --soft <commit_id>
      
    • Hard reset (discards all changes):
        git reset --hard <commit_id>
      

Example Workflow

  1. Initialize a Repository:

     git init
    
  2. Add a Remote Repository:

     git remote add origin https://github.com/username/repository.git
    
  3. Make Changes and Check Status:

     git status
    
  4. Stage Changes:

     git add .
    
  5. Commit Changes:

     git commit -m "Initial commit"
    
  6. Push Changes to Remote Repository:

     git push -u origin master
    

This set of commands covers most of the basic operations you will need to manage your Git repositories effectively.

Common screen commands

 To create screen

screen -S <screen_name>

To detach screen

Ctrl+A d

To list screens

screen -ls

To reattch screen

screen -r <screen_name>

To detach screen already attached in some other [SSH] session

screen -d <screen_name>

To kill a screen session

screen -X -S <screen_name>; or screen -X -S <screen_name> quit

To switch to a screen

screen -r <screen_name>

Note: <screen_name> can be screenName or screenId as you get from "screen -ls" command

How to set LD_LIBRARY_PATH path in Environment Variable for using cppcms (chatgpt ans)

 ### Option 1: Setting the `LD_LIBRARY_PATH` Environment Variable


You can temporarily add the directory containing `libcppcms.so.2` to the `LD_LIBRARY_PATH` environment variable.


```sh

export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

./learnCppcms -c config.js

```


Replace `/usr/local/lib` with the actual path to the directory where `libcppcms.so.2` is installed.


### Option 2: Adding the Library Path to `/etc/ld.so.conf`


For a more permanent solution, you can add the library directory to the `/etc/ld.so.conf` file and run `ldconfig` to update the linker cache.


1. Open `/etc/ld.so.conf` in a text editor with root permissions:


    ```sh

    sudo nano /etc/ld.so.conf

    ```


2. Add the directory containing `libcppcms.so.2` (e.g., `/usr/local/lib`).


3. Save the file and exit the text editor.


4. Run `ldconfig` to update the linker cache:


    ```sh

    sudo ldconfig

    ```


### Option 3: Using a Wrapper Script


You can create a simple shell script to set the `LD_LIBRARY_PATH` environment variable before running your application:


1. Create a file named `run_learnCppcms.sh`:


    ```sh

    nano run_learnCppcms.sh

    ```


2. Add the following content to the file:


    ```sh

    #!/bin/bash

    export LD_LIBRARY_PATH=/usr/local/lib:$LD_LIBRARY_PATH

    ./learnCppcms -c config.js

    ```


    Replace `/usr/local/lib` with the actual path to the directory where `libcppcms.so.2` is installed.


3. Make the script executable:


    ```sh

    chmod +x run_learnCppcms.sh

    ```


4. Run your application using the script:


    ```sh

    ./run_learnCppcms.sh

    ```


### Additional Steps


1. **Ensure Libraries are Installed**: Verify that `libcppcms.so.2` is actually installed on your system. You can search for the file using:


    ```sh

    sudo find / -name libcppcms.so.2

    ```


2. **Check Symbolic Links**: Sometimes the issue is caused by missing symbolic links. Ensure that `libcppcms.so.2` is correctly linked in your library directory. For example, if the actual file is `libcppcms.so.2.0.0`, you might need to create a symlink:


    ```sh

    sudo ln -s /path/to/libcppcms.so.2.0.0 /usr/local/lib/libcppcms.so.2

    ``

Regarding site Free Browser Tool (https://free-browser-tools.mohitkrgupta.dev) (discussion with google search AI)

Various discussions with Google Search AI regarding site  Free Browser Tool are as below: site free-browser-tools.mohitkrgupta.dev what doe...