Skip to content

Commit

Permalink
doc: stdout/stderr can block when directed to file
Browse files Browse the repository at this point in the history
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>
  • Loading branch information
bnoordhuis authored and jasnell committed Dec 23, 2015
1 parent 2064de0 commit 0369986
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

Expand Down

0 comments on commit 0369986

Please sign in to comment.