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764What the preprocessor actually does
765The `#include` directive for standard headers
766The `#include` directive for local files
767How `gcc -E` shows preprocessor output
768Defining constants with `#define`
769Removing definitions with `#undef`
770The danger of semicolon in `#define`
771Avoiding magic numbers with macros
772Defining function-like macros
773Why parenthesize macro arguments
774Why parenthesize the whole macro expression
775Side effects in macro arguments
776The stringizing operator `#`
777The token-pasting operator `##`
778Macros vs inline functions
779Multi-line macros with backslashes
780Using `#ifdef` and `#ifndef`
781Basic logic with `#if` and `#else`
782The `defined()` operator
783Testing for platform-specific code
784Using `#error` to stop compilation
785Temporary code disabling with `#if 0`
786Feature toggles via command line `-D`
787Managing debug prints with macros
788The purpose of header files
789The 'duplicate definition' error
790Creating basic include guards
791How `#pragma once` works
792Forward declarations in headers
793What should NOT go in a header
794Circular dependency issues
795Standard header search paths
796Splitting code into `.c` and `.h`
797The `extern` keyword for variables
798Static functions for file scoping
799The role of the 'main' file
800Organizing /src and /include folders
801Naming conventions for large projects
802Dependency graphing in your head
803From source code to object files
804The `-c` flag for compilation
805What is inside a `.o` file
806Linking multiple object files
807Understanding 'undefined reference' errors
808The executable ELF format
809Symbol tables and visibility
810What is a static library `.a`
811Creating archives with the `ar` tool
812Linking with static libraries
813What is a shared library `.so` / `.dll`
814Position Independent Code `-fPIC`
815Linking with shared libraries `-l` and `-L`
816Runtime library loading and `LD_LIBRARY_PATH`
817Why we need build tools
818Structure of a Makefile Rule
819Targets, dependencies, and recipes
820The importance of Tab characters
821Using variables in Makefiles
822Automatic variables like `$@` and `$<`
823Phony targets like `clean` and `all`
824Incremental builds and file timestamps
825Compiling with debug symbols `-g`
826Starting GDB with an executable
827The `run` and `quit` commands
828Listing source code with `list`
829Setting breakpoints with `break`
830Stepping through code with `next` and `step`
831Continuing execution with `continue`
832Checking variable values with `print`
833Inspecting the call stack with `backtrace`
834Moving between frames with `up` and `down`
835Setting conditional breakpoints
836Using `watch` for memory changes
837Debugging a Segfault from a core dump
838Attaching GDB to a running process
839Examining raw memory with `x`

764What the preprocessor actually does
765The `#include` directive for standard headers
766The `#include` directive for local files
767How `gcc -E` shows preprocessor output
768Defining constants with `#define`
769Removing definitions with `#undef`
770The danger of semicolon in `#define`
771Avoiding magic numbers with macros
772Defining function-like macros
773Why parenthesize macro arguments
774Why parenthesize the whole macro expression
775Side effects in macro arguments
776The stringizing operator `#`
777The token-pasting operator `##`
778Macros vs inline functions
779Multi-line macros with backslashes
780Using `#ifdef` and `#ifndef`
781Basic logic with `#if` and `#else`
782The `defined()` operator
783Testing for platform-specific code
784Using `#error` to stop compilation
785Temporary code disabling with `#if 0`
786Feature toggles via command line `-D`
787Managing debug prints with macros
788The purpose of header files
789The 'duplicate definition' error
790Creating basic include guards
791How `#pragma once` works
792Forward declarations in headers
793What should NOT go in a header
794Circular dependency issues
795Standard header search paths
796Splitting code into `.c` and `.h`
797The `extern` keyword for variables
798Static functions for file scoping
799The role of the 'main' file
800Organizing /src and /include folders
801Naming conventions for large projects
802Dependency graphing in your head
803From source code to object files
804The `-c` flag for compilation
805What is inside a `.o` file
806Linking multiple object files
807Understanding 'undefined reference' errors
808The executable ELF format
809Symbol tables and visibility
810What is a static library `.a`
811Creating archives with the `ar` tool
812Linking with static libraries
813What is a shared library `.so` / `.dll`
814Position Independent Code `-fPIC`
815Linking with shared libraries `-l` and `-L`
816Runtime library loading and `LD_LIBRARY_PATH`
817Why we need build tools
818Structure of a Makefile Rule
819Targets, dependencies, and recipes
820The importance of Tab characters
821Using variables in Makefiles
822Automatic variables like `$@` and `$<`
823Phony targets like `clean` and `all`
824Incremental builds and file timestamps
825Compiling with debug symbols `-g`
826Starting GDB with an executable
827The `run` and `quit` commands
828Listing source code with `list`
829Setting breakpoints with `break`
830Stepping through code with `next` and `step`
831Continuing execution with `continue`
832Checking variable values with `print`
833Inspecting the call stack with `backtrace`
834Moving between frames with `up` and `down`
835Setting conditional breakpoints
836Using `watch` for memory changes
837Debugging a Segfault from a core dump
838Attaching GDB to a running process
839Examining raw memory with `x`

Lesson 782 of 1,219·11. The Preprocessor and BuildPro lesson

The `defined()` operator

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