Number of elements in a channel

http://golang.org/pkg/builtin/#len

func len(v Type) int
The len built-in function returns the length of v, according to its type:

• Array: the number of elements in v.
• Pointer to array: the number of elements in *v (even if v is nil).
• Slice, or map: the number of elements in v; if v is nil, len(v) is zero.
• String: the number of bytes in v.
• Channel: the number of elements queued (unread) in the channel buffer; if v is nil, len(v) is zero.

package main

import "fmt"

func main() {
        c := make(chan int, 100)
        for i := 0; i < 34; i++ {
                c <- 0
        }
        fmt.Println(len(c))
}

will output:

34