What is a cgo?

A cgo, short for "cgo is a foreign function interface for the Go programming language," is a mechanism that allows Go code to call C functions and use C libraries. It enables Go programs to interoperate with existing C code and leverage C libraries without having to rewrite everything in Go.

With cgo, Go code can interface directly with C code by defining special Go files that contain C function signatures, using special Go build tags, and calling C functions from within the Go code. This makes it easier for developers to integrate existing C libraries into their Go applications and access low-level system functions that are not available in the Go standard library.

However, using cgo can introduce complexity and potential performance overhead to Go programs, as it requires extra C compilation steps and the overhead of marshaling data between Go and C types. Therefore, it is usually recommended to use cgo sparingly and only when necessary for integrating with existing C code or libraries.