10.3 The Package Declaration
A package
declaration is required at the start of every Go source file.
Its main purpose is to determine the default identifier for that package
(called the package name) when it is imported by another
package.
For example, every file of the math/rand
package starts with
package rand
, so when you import this package, you can access
its members as rand.Int
, rand.Float64
, and so on.
package main import ( "fmt" "math/rand" ) func main() { fmt.Println(rand.Int()) }
Conventionally, the package name is the last segment of the
import path, and as a result, two packages may have the same name
even though their import paths necessarily differ. For example, the
packages whose import paths are math/rand
and crypto/rand ...
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