1. Create a .go file with this format

package main

/*
#include <stdlib.h> // Include the C standard library for memory management functions
*/
import "C"      // Import the C language features for interoperability
import "unsafe" // Import unsafe for pointer manipulation

// Fibonacci computes the first n Fibonacci numbers and returns a pointer to an array of integers.
// It takes an integer n (C.int) as an argument, which represents how many Fibonacci numbers to compute.
//
//export Fibonacci
func Fibonacci(n C.int) *C.int {
	// Allocate memory for the result array in C
	// Using C.malloc to allocate memory for an array of integers (size of n).
	result := C.malloc(C.size_t(n) * C.size_t(unsafe.Sizeof(C.int(0))))

	// Typecast the result pointer to a Go slice to populate it.
	// The slice will allow us to easily access and modify the allocated memory.
	resultSlice := (*[1 << 30]C.int)(result)[:n:n] // Create a slice of C.int from the allocated memory

	// Initialize the first two Fibonacci numbers
	if n > 0 {
		resultSlice[0] = 0 // First Fibonacci number
	}
	if n > 1 {
		resultSlice[1] = 1 // Second Fibonacci number
	}

	// Compute the Fibonacci sequence from the third number onward
	for i := 2; i < int(n); i++ {
		resultSlice[i] = resultSlice[i-1] + resultSlice[i-2] // F(n) = F(n-1) + F(n-2)
	}

	// Print a message indicating that the Go code is running
	print("You're running the Go code\\n")

	// Return a pointer to the allocated C array containing Fibonacci numbers
	return (*C.int)(result)
}

// The main function is not needed for the library
// It is left empty to comply with the requirements of cgo, which needs a main function
// if the file is compiled into an executable, but here it will be built as a shared library.
func main() {}

2. Then change directory to the folder which contains the go code and type

go build -buildmode=c-archive -o libfibonacci.a .

This will give you libfibonacci.h and libfibonacci.a files.

3. Now create a Swift Project named GoWrapperMacApp

3.1 Add the libfibonacci.h and libfibonacci.a file in your xcode project

3.2 Create a header file name “GoWrapperMacApp-Bridging-Header.h”

#include "libfibonacci.h"

3.3 Project Target → Build Settings → Objective-C Bridging Header

$(PROJECT_DIR)/GoWrapperMacApp/GoWrapperMacApp-Bridging-Header.h

3.4 Create a swift file name “FibonacciWrapper”