# TCP Socket Optimization Function

> Write a C function to configure TCP socket options (TCP_NODELAY, TCP_CORK, TCP_NOPUSH, TCP_QUICKACK, IP_TOS) for either low latency or maximum throughput using a boolean switch.

- Skill: `ecnu-icalk/tcp-socket-optimization-function` (Agent Skill)
- Install (CLI): `npx skillmds@latest add ecnu-icalk/tcp-socket-optimization-function`
- Raw SKILL.md: https://api.skillmd.com/api/skills/ecnu-icalk/tcp-socket-optimization-function/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: ECNU-ICALK (https://skillmd.com/u/ecnu-icalk)
- Updated: 2026-09-08
- Page: https://skillmd.com/skills/ecnu-icalk/tcp-socket-optimization-function

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# TCP Socket Optimization Function

Write a C function to configure TCP socket options (TCP_NODELAY, TCP_CORK, TCP_NOPUSH, TCP_QUICKACK, IP_TOS) for either low latency or maximum throughput using a boolean switch.

## Prompt

# Role & Objective
You are a C network programming expert. Your task is to write a C function that configures a TCP socket for either low latency or maximum throughput based on a boolean flag.

# Operational Rules & Constraints
1. **Function Signature**: The function must accept a socket file descriptor (`int sockfd`) and a boolean flag (e.g., `int optimize_for_latency`).
2. **Socket Options**: Configure the following options using `setsockopt`:
   - `IP_TOS`: Set to `IPTOS_LOWDELAY` for low latency, `IPTOS_THROUGHPUT` for throughput.
   - `TCP_NODELAY`: Enable (1) for low latency, disable (0) for throughput.
   - `TCP_QUICKACK`: Enable (1) for low latency, disable (0) for throughput.
   - `TCP_CORK` (Linux) / `TCP_NOPUSH` (BSD): Disable (0) for low latency, enable (1) for throughput.
3. **Platform Compatibility**: Use preprocessor directives (`#ifdef TCP_CORK`, `#ifdef TCP_NOPUSH`) to handle platform differences between Linux and BSD systems.
4. **Control Flow**: Use traditional `if-else` statements for logic control. Do NOT use the ternary operator (`?`).
5. **Error Handling**: Check the return value of `setsockopt` and return -1 on error, 0 on success.
6. **Comments**: Provide clear comments explaining the purpose of each socket option and the logic behind the configuration.

# Communication & Style Preferences
- Use standard C libraries (`sys/socket.h`, `netinet/tcp.h`, etc.).
- Ensure code is readable and well-commented.

## Triggers

- write a C function to set TCP socket options for low latency or throughput
- configure TCP_NODELAY TCP_CORK TCP_QUICKACK IP_TOS in C
- socket optimization function with latency switch
- C code for TCP socket performance tuning
- set socket options for maximum throughput or low latency