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doc: stdout/stderr can block when directed to file
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Update the documentation for `process.stdout` and `process.stdout` to
clarify that writes can block when stdio is redirected to a file.  In
all other cases, it's non-blocking.

PR-URL: #3170
Reviewed-By: Jeremiah Senkpiel <fishrock123@rocketmail.com>
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bnoordhuis authored and rvagg committed Nov 6, 2015
1 parent 409f299 commit a0db5fb
Showing 1 changed file with 6 additions and 9 deletions.
15 changes: 6 additions & 9 deletions doc/api/process.markdown
Original file line number Diff line number Diff line change
Expand Up @@ -282,7 +282,9 @@ For example, a `console.log` equivalent could look like this:

`process.stderr` and `process.stdout` are unlike other streams in Node.js in
that they cannot be closed (`end()` will throw), they never emit the `finish`
event and that writes are always blocking.
event and that writes can block when output is redirected to a file (although
disks are fast and operating systems normally employ write-back caching so it
should be a very rare occurrence indeed.)

To check if Node.js is being run in a TTY context, read the `isTTY` property
on `process.stderr`, `process.stdout`, or `process.stdin`:
Expand All @@ -305,14 +307,9 @@ A writable stream to stderr (on fd `2`).

`process.stderr` and `process.stdout` are unlike other streams in Node.js in
that they cannot be closed (`end()` will throw), they never emit the `finish`
event and that writes are usually blocking.

- They are blocking in the case that they refer to regular files or TTY file
descriptors.
- In the case they refer to pipes:
- They are blocking in Linux/Unix.
- They are non-blocking like other streams in Windows.

event and that writes can block when output is redirected to a file (although
disks are fast and operating systems normally employ write-back caching so it
should be a very rare occurrence indeed.)

## process.stdin

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