mysocket

mysocket is a minimal C library that wraps the POSIX socket API for simple blocking TCP connections over IPv4. It reduces the boilerplate of socket programming in C down to four calls: listen-and-accept, connect, write and read.

This library was created to reduce the boilerplate of socket programming in C, while keeping everything simple and hackable. It is used by my FileTransfer project.

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🔧 Features

• ✅ Lightweight: one .c and one .h, no dependencies beyond libc
• 📡 Blocking TCP (IPv4) sockets
• 🖥️ Server side: create_socket() binds to 0.0.0.0:<port>, listens and returns the accepted client's file descriptor
• 🔌 Client side: connect_socket() connects to a dotted-quad IPv4 address
• 🧠 Great for learning or quick prototyping

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🗂️ Repository Structure

mysocket/
├── msocket.h          # Public API
├── msocket.c          # Implementation
├── examples/
│   ├── example.c      # Interactive server/client using the library
│   ├── server.c       # Standalone getaddrinfo() UDP echo server, IPv4/IPv6 (does not use the library)
│   └── client.c       # Matching UDP client (does not use the library)
├── makefile           # Builds examples/example
└── README.md

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🚀 Quick Start

🔨 Build

git clone https://github.com/Gedankenn/mysocket.git
cd mysocket
make            # builds examples/example from examples/example.c + msocket.c

▶️ Run the example

./examples/example server 5555              # terminal 1
./examples/example client 5555 127.0.0.1    # terminal 2: type lines, the server prints them

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🧪 Example Code

#include "msocket.h"
#include <stdio.h>
#include <string.h>

int main(void) {
    /* server: blocks until a client connects, returns the client's fd */
    int cfd = create_socket("5555");
    if (cfd < 0) return 1;

    char buf[BUF];
    int n = socket_read(cfd, buf, sizeof(buf) - 1);
    if (n > 0) {
        buf[n] = '\0';
        printf("got: %s\n", buf);
        socket_write(cfd, "ok", 2);
    }
    close(cfd);
    return 0;
}

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📘 API Reference (msocket.h)

int create_socket(char *port);

Creates a TCP socket, binds it to 0.0.0.0:<port>, listens and blocks until one client connects. Returns the connected client's file descriptor, or SOCKET_ERROR (-1).

int connect_socket(char *host, char *port);

Connects to host (IPv4 address string, e.g. "192.168.0.10") on port. Returns the socket file descriptor, or SOCKET_ERROR.

int socket_write(int sfd, void *data, int size);

Sends size bytes. Returns the number of bytes sent, or -1.

int socket_read(int sfd, void *data, int buf_size);

Receives up to buf_size bytes into data. Returns the number of bytes read (0 when the peer closed), or -1.

Constants: SOCKET_SUCCESS (0), SOCKET_ERROR (-1), BUF (4096), IPV4/IPV6 and EXIT ("/-!EXIT!-/").

IPv6 is not supported yet (the implementation uses AF_INET).

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🛠️ Use in Your Project

Copy (or add as a git submodule) msocket.c and msocket.h, then compile them with your code:

gcc your_app.c msocket.c -I. -o your_app

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🤝 Contributing

This is a personal utility project, but contributions are welcome.

• Found a bug? Open an issue.
• Have an idea? Open a discussion or PR.
• Want to use this in an embedded system or with non-blocking I/O? Fork away!

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📄 License

This project is licensed under the MIT License.

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👤 Author

Developed by Fabio Slika Stella
Engineer passionate about C, Linux, embedded systems, and clean design.

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⭐️ Show Support

If you find this project useful, give it a ⭐ on GitHub!