Modern Chan Channel Count

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Count

Returns how many values are buffered right now, as a snapshot.

Syntax

Count( ) as int32

Notes

• A snapshot, and stale the moment it returns if another thread is running -- never branch on it to decide whether a send or receive will block. Use TrySend/TryReceive, which cannot race.
• Always 0 on a rendezvous channel (capacity 0): a value handed over directly is never buffered.
• Not to be confused with WaitGroup.Count, which counts outstanding work rather than queued values.

Examples

#import "std/tasks"
using tasks

dim ch as Channel( of int32 ) = Channel( of int32 )( 4 )
print ch.Count( )            '' 0

dim as int32 v = 1
ch.Send( v )
print ch.Count( )            '' 1

'' A rendezvous channel never buffers, so its Count stays 0
dim r as Channel( of int32 ) = Channel( of int32 )( 0 )
print r.Capacity( )          '' 0
print r.Count( )             '' 0

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