How to Call C from Go with Cgo

You call C functions from Go by defining a C preamble in a comment block, importing the pseudo-package "C", and prefixing C identifiers with C. in your Go code.

package main

/*
#include <stdio.h>
*/
import "C"

func main() {
	C.printf("Hello from C\n")
}

1. Write C code or #include directives in a comment block immediately before import "C".
2. Add import "C" to your import list to enable cgo processing.
3. Call C functions using the C. prefix, such as C.printf or C.malloc.
4. Compile the file with go build to generate the necessary C wrapper and link the binary.

Cgo lets your Go program talk directly to existing C libraries, like using a translator to speak a different language. You write a small bridge in your Go file that tells the compiler which C code to include and how to call it. This is useful when you need high-performance math or access to system tools that only exist in C.