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// run
// Copyright 2009 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Test the cap predeclared function applied to channels.
package main
import (
"strings"
"unsafe"
)
type T chan int
const ptrSize = unsafe.Sizeof((*byte)(nil))
func main() {
c := make(T, 10)
if len(c) != 0 || cap(c) != 10 {
println("chan len/cap ", len(c), cap(c), " want 0 10")
panic("fail")
}
for i := 0; i < 3; i++ {
c <- i
}
if len(c) != 3 || cap(c) != 10 {
println("chan len/cap ", len(c), cap(c), " want 3 10")
panic("fail")
}
c = make(T)
if len(c) != 0 || cap(c) != 0 {
println("chan len/cap ", len(c), cap(c), " want 0 0")
panic("fail")
}
n := -1
shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
shouldPanic("makechan: size out of range", func() { _ = make(T, int64(n)) })
if ptrSize == 8 {
// Test mem > maxAlloc
var n2 int64 = 1 << 59
shouldPanic("makechan: size out of range", func() { _ = make(T, int(n2)) })
// Test elem.size*cap overflow
n2 = 1<<63 - 1
shouldPanic("makechan: size out of range", func() { _ = make(T, int(n2)) })
} else {
n = 1<<31 - 1
shouldPanic("makechan: size out of range", func() { _ = make(T, n) })
shouldPanic("makechan: size out of range", func() { _ = make(T, int64(n)) })
}
}
func shouldPanic(str string, f func()) {
defer func() {
err := recover()
if err == nil {
panic("did not panic")
}
s := err.(error).Error()
if !strings.Contains(s, str) {
panic("got panic " + s + ", want " + str)
}
}()
f()
}
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