├── src/
│   ├── 1-blocking-echo-server.c                    # Basic blocking single-client server
│   ├── 2-non-blocking-echo-server.c                # Non-blocking single connection
│   ├── 3-non-blocking-multi-conn-echo-server.c     # Non-blocking multiple connections
│   ├── 4-blocking-multithread-echo-server.c        # Thread-per-connection model
│   ├── 5-blocking-threadpool-echo-server.c         # Thread pool implementation
│   ├── 6-select-echo-server.c                      # I/O multiplexing with select()
│   ├── 7-poll-echo-server.c                        # I/O multiplexing with poll()
│   ├── 8-epoll-echo-server.c                       # I/O multiplexing with epoll()
│   ├── multithreading/                             # Multithreading concepts
│   │   ├── 1-basics.c                              # Thread creation and joining
│   │   ├── 2-race-condition-problem.c              # Race condition demonstration
│   │   ├── 3-mutex.c                               # Mutual exclusion
│   │   ├── 4-producer-consumer-problem.c           # Classic concurrency problem
│   │   ├── 5-condition-variables.c                 # Thread synchronization
│   │   ├── 6-barrier.c                             # Thread barriers
│   │   ├── 7-semaphore.c                           # Semaphore usage
│   │   ├── 8-producer-consumer-semaphore.c         # Producer-consumer with semaphores
│   │   ├── 9-atomics.c                             # Atomic operations
│   │   └── 10-thread-pool.c                        # Thread pool pattern
│   └── select-poll-epoll/                          # I/O multiplexing basics
│       ├── 1-select-basics.c                       # select() fundamentals
│       ├── 2-poll-basics.c                         # poll() fundamentals
│       └── 3-epoll-basics.c                        # epoll() fundamentals
├── bin/                                            # Compiled binaries
└── Makefile                                        # Build configuration