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gdb.txt

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+Flags for compiling the code:
+------------------------------
+
+-W: Warnings
+-Wall: To detect all the warnings. By all warnings means, most
+        commonly used warnings.
+
+-Wconversion: To warns use about implicit type conversion.
+
+-Werror: To treat all the warnings as errors.
+
+
+Some codes in C++ implicitly provides warning even if
+we don't mentions warnings flags.
+
+For ex:
+    int x{square(i)};
+
+    Here, square function returns a float value. But, curly
+    braces initialization gives warning for conversion (implicit-conversion,
+    narrowing-conversion).
+
+
+
+Printing values to check and debugging:
+--------------------------------------
+
+We can use -D flag to do #define a macro from
+compile command itself.
+
+For ex:
+gcc -DDEBUG <code>.c -o <exe>
+
+Same as doing #define DEBUG 1
+
+
+
+
+
+GDB (GNU Debugger):
+--------------------
+
+Command: gdb --version
+    To see the version of gdb.
+
+
+Command: gdb --silent ./<exe>
+
+    To to print all the info that gdb prints while starting.
+
+Command: gdb --tui
+
+    To run gdb in Text-user interface mode.
+    To open TUI when gdb is already On.
+
+    use command: layout src
+    
+ 
+We can use these flags with gcc for C code or g++ for C++ code.
+
+Note: To use gdb with compiled code. We need to compile the source 
+        code with '-g' flag this will compile the source code and
+        generate executable along with Debug symbol which will be used
+        by GDB.
+
+        Also, it is not advisable to optimize the code with flags like
+        -O3, etc and if the compiler by default optimize the code, we
+        can disable it by using -O0. We do this because, optimization
+        introduce extra code and make the debugging more complex.
+
+Command: gdb ./<executable>
+
+    To run gdb with given argument as the program to debug.
+
+
+--------------------------------------------------------------------------------------------------
+
+
+GDB commands:
+-------------
+
+Command: quit or q
+
+    To quit out of current gdb session.
+
+
+Command: run or r
+
+    To run the executable in gdb.
+
+Command: CTRL + l
+
+    To clear screen in gdb.
+
+Command: start
+
+    It will add temporary breakpoint to start
+    of the execution i.e. at the main() function
+    and stop the execution.
+
+Command: next or n
+
+    To move to next line of code and execute it.
+    Next statement and execute it.
+
+
+Command: step or s
+
+    To move into the function execution instead of
+    just executing the function and returning the result.
+
+
+Command: finish or fin
+
+    To step out of the function.
+
+Command: list or l
+
+
+    To show some context of the current execution w.r.t
+    code
+
+
+        To show some context of the current execution w.r.t
+        code
+    
+    Also using command "list <line-number>" prints the 
+    context w.r.t given line number.
+
+Command: set listsize <size>
+
+    To show more content while using list command
+
+
+Command: print <variable-name> or p <variable-name>
+
+    To print the current value of the variable name.
+    It also de-reference operator to show the content
+    as well to print the value present at the address
+    in form of structure.
+
+    for ex:
+
+        print l->root
+
+        address with pointer type specified
+        
+        print *l.root
+
+        print the whole structure of the object.
+
+
+Command: c or continue
+
+    To continue the execution till next breakpoint
+    or termination of program.
+
+Command: whatis <type>
+
+    To specify what is symbol which maybe user-defined
+    actually is....
+
+    For ex:
+
+    whatis list_t
+    type = struct list
+
+
+Command: ptype <type>
+
+    It gives more information as compare to whatis.
+
+    For ex:
+    ptype list_t
+    type = struct list{
+        node_t *root;
+    }
+
+
+    Note: Both ptype and whatis can be used with variable as well
+
+
+Command: info scope <argument>
+
+    To show what is present in the scope of the current function in execution.
+
+
+Commaond: info types
+
+    To list all the different type of symbols in the program.
+
+
+Command: tbreak <line-number>
+
+    To give temporary breakpoint to the program.
+    This breakpoint will stop the program execution only once.
+
+Command: info breakpoints
+
+    To show some information about breakpoints.
+
+Command: break <line-number>
+
+    These are permanent breakpoint
+
+Command: break <line-number>
+
+    These are permanent breakpoint
+
+Command: layout src
+
+    To open the TUI with src code.
+
+Command: help layout
+
+    To know more about layout.
+
+Command: layout reg
+
+    To show register info.
+
+Command: layout asm
+
+    To show asm info.
+
+Command: CTRL+x 1,2...
+
+    To cycle through various layout for a single window.
+
+Command: CTRL+x 0
+
+    To navigate to gdb terminal and TUI window
+
+
+    If view gets messed up use CTRL+l
+
+
+    If view gets messed up use CTRL+l
+
+    Same thing for navigation can be done 
+    using focus cmd and focus src window.
+
+Command: CTRL+p
+
+    will move to previous command if focus is on src window.
+
+
+Command: winheight src -2
+
+    To change the size of window passed as an argument. In
+    this case, decrease by 2.