# socket-samples

Socket programming examples in strict C90 and modern Python3.

## Build & Run C90 Examples

```
make clean && make all
```
Builds 9 binaries in `build/` (strict `-std=c90 -pedantic -Wall -Wextra -Werror`).

Port: **9999**

All use the same **custom binary protocol**:
- Header: `1-byte type + 2-byte BE16 length`
- Types: `PING(0x01)`, `PONG(0x02)`, `METRIC_REQ(0x03)`, `METRIC_RESP(0x04)`, `SUBSCRIBE(0x05)`, `PUSH(0x06)`, `UNSUB(0x07)`, `ERROR(0xFF)`
- Metrics: `cpu`, `memory`, `disk`, `loadavg`, `uptime` (simulated)

### C90 Clients
- `src/c90/metric_client.c`: Basic interactive TCP client (ping/get/quit).
- `src/c90/metric_client_ansi.c`: Advanced TCP client w/ `select()` + unsubscribe.
- `src/c90/metric_client_sub.c`: TCP client w/ live subscribe/push via `select()`.
- `src/c90/metric_client_udp.c`: Full-featured UDP client (get/sub/unsub).
- `src/c90/perf_client_udp.c`: UDP perf tester (`--flood` or subscribe mode, 30s throughput).

### C90 Servers
- `src/c90/metric_server.c`: Iterative TCP server (single client).
- `src/c90/metric_server_fork.c`: Forking TCP server (multi-client).
- `src/c90/metric_server_fork_sub.c`: Forking TCP server w/ subscribe/push.
- `src/c90/metric_server_udp.c`: UDP server w/ subscriber management (`select()`).

## Python Examples

Run: `python3 src/python/<file>.py [host [port]]`

Port: **9999** (metrics), **65432** (echo)

### Echo (text protocol)
- `src/python/echo_client.py`: Interactive TCP echo client.
- `src/python/echo_server.py`: Iterative TCP echo server.

### Metrics (same binary protocol as C90)
- `src/python/metric_client.py`: Threaded TCP client (ping/get).
- `src/python/metric_server.py`: Threaded multi-client TCP server.

### Monitor (advanced w/ subscribe/push)
- `src/python/mon_client.py`: Full TCP client (ping/get/sub).
- `src/python/mon_server.py`: Threaded TCP server w/ subscribe/push support.