Function std.process.wait
Waits for the process associated with pid to terminate, and returns
its exit status.
In general one should always wait for child processes to terminate
before exiting the parent process unless the process was spawned as detached
(that was spawned with Config flag).
Otherwise, they may become "zombies"
– processes that are defunct, yet still occupy a slot in the OS process table.
You should not and must not wait for detached processes, since you don't own them.
If the process has already terminated, this function returns directly.
The exit code is cached, so that if wait() is called multiple times on
the same Pid it will always return the same value.
POSIX specific
If the process is terminated by a signal, this function returns a
negative number whose absolute value is the signal number.
Since POSIX restricts normal exit codes to the range 0-255, a
negative return value will always indicate termination by signal.
Signal codes are defined in the core module
(which corresponds to the signal POSIX header).
Throws
ProcessException on failure or on attempt to wait for detached process.
Example
See the spawnProcess documentation.
See also
tryWait, for a non-blocking function.
Authors
Lars Tandle Kyllingstad, Steven Schveighoffer, Vladimir Panteleev