Modern Chan Channel TryReceive

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TryReceive

Receives a value only if one is ready; returns false if empty or closed.

Syntax

TryReceive( byref out as T ) as boolean

Notes

• FALSE means "nothing right now", and also means closed-and-drained. IsClosed distinguishes them.
• The output is left alone when it answers FALSE.
• Use it to poll a channel from a loop that has other work to do.

Examples

#import "std/tasks"
using tasks

dim ch as Channel( of int32 ) = Channel( of int32 )( 4 )

dim as int32 got
print ch.TryReceive( got )   '' false -- empty, and it did not wait

dim as int32 v = 7
ch.Send( v )
print ch.TryReceive( got )   '' true
print got                    '' 7

'' FALSE covers both "empty" and "closed and drained"
ch.Close( )
print ch.TryReceive( got )   '' false
print ch.IsClosed( )         '' true -- which tells the two apart

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Library: Goroutines and Channels
Category: Goroutines and Channels
Documented under: Members