# cgo-cpp

**Repository Path**: mirrors_ingydotnet/cgo-cpp

## Basic Information

- **Project Name**: cgo-cpp
- **Description**: No description available
- **Primary Language**: Unknown
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2025-08-21
- **Last Updated**: 2026-02-21

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

CGO + C++ Library Example
=========================

This project demonstrates how to create a Go program that calls C++ functions
through CGO, resulting in a single binary executable.


## Project Structure

- `cpplib.hpp` - C++ header file with function declarations
- `cpplib.cpp` - C++ implementation of the library functions
- `main.go` - Go program that calls C++ functions
- `Makefile` - Build system for the entire project


## Features

The C++ library provides various functions with different argument and return
types:

- **Integer operations**: `add`, `multiply`, `factorial`
- **String operations**: `get_greeting`, `string_length`, `repeat_string`
- **Float operations**: `divide`, `power`
- **Array operations**: `reverse_array`, `sum_array`
- **Boolean operations**: `is_even`, `is_positive`


## Using the Makefile

This Makefile will automatically install Go inside the working directory.
It assumes G++ is installed.

```bash
# Build the binary
make build

# Build and run the binary
make run

# Clean the build artifacts
make clean

# Clean the Go cache
make distclean
```


## How It Works

1. The Makefile first compiles the C++ code into a static library
   (`libcpplib.a`)
2. The Go program uses CGO directives to statically link against this library
3. The final result is a single, completely static binary executable
   (`cgo-demo`)
4. The Go program demonstrates calling various C++ functions with different
   data types

## CGO Directives

The Go program uses these CGO directives:

```go
/*
#cgo CXXFLAGS: -std=c++11
#cgo LDFLAGS: -L. -lcpplib -lstdc++
#include "cpplib.hpp"
*/
import "C"
```

This tells the Go compiler to:
- Use C++11 standard
- Link against the local `libcpplib.a` static library
- Include the C++ standard library and math library
- Include our custom header file


## Notes

- The C++ functions are wrapped in `extern "C"` to ensure C linkage
- Memory management is handled properly with `C.free()` for C strings
- The build process creates a static library that gets fully linked into the final binary
- The resulting executable is completely self-contained with no external dependencies

## Function Details

### String Operations
- `get_greeting(name)`: Returns a greeting string with the given name
- `string_length(str)`: Returns the length of a string
- `repeat_string(str, times)`: Returns the input string repeated the specified number of times
  - Handles edge cases: empty strings, zero/negative times return empty strings
  - Efficiently manages memory for repeated strings