This page is a snapshot from the LWG issues list, see the Library Active Issues List for more information and the meaning of CD1 status.
Section: 184.108.40.206 [ostream.manip] Status: CD1 Submitter: PremAnand M. Rao Opened: 2001-08-27 Last modified: 2019-01-01
Priority: Not Prioritized
View all issues with CD1 status.
A footnote in 220.127.116.11 [ostream.manip] states:
[Footnote: The effect of executing cout << endl is to insert a newline character in the output sequence controlled by cout, then synchronize it with any external file with which it might be associated. --- end foonote]
Does the term "file" here refer to the external device? This leads to some implementation ambiguity on systems with fully buffered files where a newline does not cause a flush to the device.
Choosing to sync with the device leads to significant performance penalties for each call to endl, while not sync-ing leads to errors under special circumstances.
I could not find any other statement that explicitly defined the behavior one way or the other.
Remove footnote 300 from section 18.104.22.168 [ostream.manip].
We already have normative text saying what endl does: it inserts a newline character and calls flush. This footnote is at best redundant, at worst (as this issue says) misleading, because it appears to make promises about what flush does.