[3.13] gh-99880: document rounding mode for new-style formatting (GH-121481) #126334
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
…onGH-121481) * pythongh-99880: document rounding mode for new-style formatting The CPython uses _Py_dg_dtoa(), which does rounding to nearest with half to even tie-breaking rule. If that functions is unavailable, PyOS_double_to_string() fallbacks to system snprintf(). Since CPython 3.12, build requirements include C11 compiler *and* support for IEEE 754 floating point numbers (Annex F). This means that FE_TONEAREST macro is available and, per default, printf-like functions should use same rounding mode as _Py_dg_dtoa(). * Update Doc/library/string.rst Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com> --------- (cherry picked from commit 7d7d56d) Co-authored-by: Sergey B Kirpichev <skirpichev@gmail.com> Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
bedevere-app
bot
added
docs
This was referenced Nov 2, 2024
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
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Outdated suggestions cannot be applied.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.
The CPython uses _Py_dg_dtoa(), which does rounding to nearest with half
to even tie-breaking rule.
If that functions is unavailable, PyOS_double_to_string() fallbacks to
system snprintf(). Since CPython 3.12, build requirements include C11
compiler and support for IEEE 754 floating point numbers (Annex F).
This means that FE_TONEAREST macro is available and, per default,
printf-like functions should use same rounding mode as _Py_dg_dtoa().
Co-authored-by: Bénédikt Tran 10796600+picnixz@users.noreply.github.com
(cherry picked from commit 7d7d56d)
Co-authored-by: Sergey B Kirpichev skirpichev@gmail.com
Co-authored-by: Bénédikt Tran 10796600+picnixz@users.noreply.github.com
📚 Documentation preview 📚: https://cpython-previews--126334.org.readthedocs.build/