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doc: child_process: document 'error' event

Fixes #5130.
v0.10.2-release
Ben Noordhuis 12 years ago
parent
commit
a80a132b38
  1. 27
      doc/api/child_process.markdown

27
doc/api/child_process.markdown

@ -26,6 +26,19 @@ which can be piped to and from.
The ChildProcess class is not intended to be used directly. Use the The ChildProcess class is not intended to be used directly. Use the
`spawn()` or `fork()` methods to create a Child Process instance. `spawn()` or `fork()` methods to create a Child Process instance.
### Event: 'error'
* `err` {Error Object} the error.
Emitted when:
1. The process could not be spawned, or
2. The process could not be killed, or
3. Sending a message to the child process failed for whatever reason.
See also [`ChildProcess#kill()`](#child_process_child_kill_signal) and
[`ChildProcess#send()`](#child_process_child_send_message_sendhandle).
### Event: 'exit' ### Event: 'exit'
* `code` {Number} the exit code, if it exited normally. * `code` {Number} the exit code, if it exited normally.
@ -125,8 +138,15 @@ be sent `'SIGTERM'`. See `signal(7)` for a list of available signals.
// send SIGHUP to process // send SIGHUP to process
grep.kill('SIGHUP'); grep.kill('SIGHUP');
Note that while the function is called `kill`, the signal delivered to the child May emit an `'error'` event when the signal cannot be delivered. Sending a
process may not actually kill it. `kill` really just sends a signal to a process. signal to a child process that has already exited is not an error but may
have unforeseen consequences: if the PID (the process ID) has been reassigned
to another process, the signal will be delivered to that process instead.
What happens next is anyone's guess.
Note that while the function is called `kill`, the signal delivered to the
child process may not actually kill it. `kill` really just sends a signal
to a process.
See `kill(2)` See `kill(2)`
@ -172,6 +192,9 @@ The `sendHandle` option to `child.send()` is for sending a TCP server or
socket object to another process. The child will receive the object as its socket object to another process. The child will receive the object as its
second argument to the `message` event. second argument to the `message` event.
Emits an `'error'` event if the message cannot be sent, for example because
the child process has already exited.
#### Example: sending server object #### Example: sending server object
Here is an example of sending a server: Here is an example of sending a server:

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