What are build tags and how are they used?

Build Tags (Build Constraints): • Conditional compilation • Include/exclude files based on conditions • OS, architecture, custom tags • Boolean expressions supported Syntax: // +build linux,amd64 // +build !windows // +build debug Or with Go 1.17+ syntax: //go:build linux && amd64 //go:build !windows //go:build debug Usage: go build -tags debug go build -tags "integration slow" Common use cases: • Platform-specific code • Debug vs release builds • Feature flags • Test environments Example: // +build integration package main func init() { // Only compiled with -tags integration }