How can I do something like the following?:
func foo(input <-chan char, output chan<- string) {
var c char
var ok bool
for {
if ThereAreValuesBufferedIn(input) {
c, ok = <-input
} else {
output <- "update message"
c, ok = <-input
}
DoSomethingWith(c, ok)
}
}
Basically, I want to check if there are buffered values in the chan so that if there aren't, I could send an update message before the thread is blocked.
package main
func foo(input <-chan char, output chan<- string) {
for {
select {
case c, ok := <-input:
if ok { // ThereAreValuesBufferedIn(input)
... process c
} else { // input is closed
... handle closed input
}
default:
output <- "update message"
c, ok := <-input // will block
DoSomethingWith(c, ok)
}
}
}
EDIT: Fixed scoping bug.
Yes, this is what the select call allows you to do. It will enable you to check one or more channels for values ready to be read.
Others have answered your question for what you wanted to do with your code (use a select), but for completeness' sake, and to answer the specific question asked by your question's title ("Is there any way to check if values are buffered in a Go chan?"), the len and cap built-in functions work as expected on buffered channels (len returns the number of buffered elements, cap returns the maximum capacity of the channel).