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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...
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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!

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If you have any doubts, please let me know.

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