Go Program Structure, Packages, main() & Compilation Model

1Concept

Go programs begin in package main inside func main(). Go compiles directly to a standalone, statically linked machine binary with no external runtime dependencies.

2Architecture Diagram

[main.go] ──► (go build) ──► [Single Static Binary (~15MB with embedded runtime & GC)]

3Code Example

package main

import (
    "fmt"
    "runtime"
)

func main() {
    fmt.Println("=== Go 1.22 Runtime Engine ===")
    fmt.Printf("Go Version: %s\n", runtime.Version())
    fmt.Printf("OS/Arch: %s/%s\n", runtime.GOOS, runtime.GOARCH)
    fmt.Printf("Active CPUs: %d\n", runtime.NumCPU())
}

4Expected Output

=== Go 1.22 Runtime Engine ===
Go Version: go1.22.2
OS/Arch: windows/amd64
Active CPUs: 8

5Key Takeaways

• ✓Every Go executable requires 'package main' and 'func main()'.
• ✓Go binaries are statically linked, making Docker images lightweight (scratch container).
• ✓Unused imports or variables cause compile-time errors in Go.