wait

wait([x])

Block the current task until some event occurs, depending on the type of the argument:

RemoteRef: Wait for a value to become available for the specified remote reference.
Channel: Wait for a value to be appended to the channel.
Condition: Wait for notify on a condition.
Process: Wait for a process or process chain to exit. The exitcode field of a process can be used to determine success or failure.
Task: Wait for a Task to finish, returning its result value. If the task fails with an exception, the exception is propagated (re-thrown in the task that called wait).
RawFD: Wait for changes on a file descriptor (see poll_fd for keyword arguments and return code)

If no argument is passed, the task blocks for an undefined period. If the task's state is set to :waiting, it can only be restarted by an explicit call to schedule or yieldto. If the task's state is :runnable, it might be restarted unpredictably.

Often wait is called within a while loop to ensure a waited-for condition is met before proceeding.

Examples

wait([x])

Block the current task until some event occurs, depending on the type of the argument.

RemoteRef: Wait for a value to become available for the specified remote reference.
```
julia> @spawn begin
         sleep(2)
         42
     end |> wait
42
```

Channel: Wait for a value to be appended to the channel.

julia> channel = Channel{Int}(1)
Channel{Int64}(sz_max:1,sz_curr:0)

julia> @async begin
         sleep(2)
         put!(channel, 42)
     end

julia> wait(channel)
42

Condition: Wait for notify on a condition.

julia> condition = Condition()
Base.Threads.Condition(0x0000000000000000, Base.Threads.SpinLock(0x0000000000000000))

julia> @async begin
         sleep(2)
         notify(condition)
     end

julia> wait(condition)

Process: Wait for a process or process chain to exit. The exitcode field of a process can be used to determine success or failure.
```
julia> process = run(`echo "Hello, Julia!"`)
Process(`echo "Hello, Julia!"`, ProcessExited(0))

julia> wait(process)
0
```
Task: Wait for a Task to finish, returning its result value. If the task fails with an exception, the exception is propagated (re-thrown in the task that called wait).
```
julia> task = @async begin
         sleep(2)
         42
     end

julia> wait(task)
42
```
RawFD: Wait for changes on a file descriptor (see poll_fd for keyword arguments and return code).
```
julia> fd = open("data.txt", "r")
IOStream(<file data.txt>)

julia> wait(fd)
```

Often wait is called within a while loop to ensure a waited-for condition is met before proceeding.

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wait

Examples

wait([x])

See Also

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