Uh oh!
There was an error while loading.Please reload this page.
- Notifications
You must be signed in to change notification settings - Fork33.5k
gh-141395: Clarify stdout flush behavior for newline characters in print()#142094
New issue
Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.
By clicking “Sign up for GitHub”, you agree to ourterms of service andprivacy statement. We’ll occasionally send you account related emails.
Already on GitHub?Sign in to your account
Open
Vemulakonda559 wants to merge12 commits intopython:mainChoose a base branch
base:main
Could not load branches
Branch not found:{{ refName }}
Loading
Could not load tags
Nothing to show
Loading
Are you sure you want to change the base?
Some commits from the old base branch may be removed from the timeline, and old review comments may become outdated.
+27 −5
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.Learn more about bidirectional Unicode characters
This PR adds a note to the print() documentation to clarify how Python’s stdout buffering works with newline (\n) characters inside a single print call.Motivation:Current documentation mentions that flush() is implied for writes containing newlines.However, it does not explain that Python flushes only after the entire write operation, not mid-string.This can confuse users coming from C, who expect a flush at each newline, and developers writing scripts that rely on immediate output for progress indicators or CLI feedback.What’s added:A .. note:: block explaining that stdout behavior depends on the environment (TTY vs redirected stdout).Guidance on explicitly flushing with flush=True or sys.stdout.flush().Mention of python -u for unbuffered output.A short example demonstrating the behavior.Impact:Improves clarity for learners and developers.Aligns documentation with actual behavior across different environments.Not a behavior change — documentation-only PR.Related Issue:Addresses issuepython#141395
Removed duplicate text and improved clarity in the note about stdout flushing behavior.
Uh oh!
There was an error while loading.Please reload this page.
Removed redundant sentence about output buffering.
Removed unnecessary comments about string flushing in print.
Remove extra blank lines and fix indentation for versionchanged directive.
Reformat output buffering explanation for clarity.
Sign up for freeto join this conversation on GitHub. Already have an account?Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Uh oh!
There was an error while loading.Please reload this page.
This PR adds a note to the print() documentation to clarify how Python’s stdout buffering works with newline (\n) characters inside a single print call.
Motivation:
Current documentation mentions that flush() is implied for writes containing newlines.
However, it does not explain that Python flushes only after the entire write operation, not mid-string.
This can confuse users coming from C, who expect a flush at each newline, and developers writing scripts that rely on immediate output for progress indicators or CLI feedback.
What’s added:
A .. note:: block explaining that stdout behavior depends on the environment (TTY vs redirected stdout).
Guidance on explicitly flushing with flush=True or sys.stdout.flush().
Mention of python -u for unbuffered output.
A short example demonstrating the behavior.
Impact:
Improves clarity for learners and developers.
Aligns documentation with actual behavior across different environments.
Not a behavior change — documentation-only PR.
Related Issue:
Addresses issue#141395
📚 Documentation preview 📚:https://cpython-previews--142094.org.readthedocs.build/