• Python 3.14 added D and F formats to the ctypes and struct module
• Python 3.15 adds D and F formats to the array module and to memoryview

The D and F formats were chosen for compatibility with numpy. Problem: in fact, numpy uses buffer formats Zd and Zf. Example:

>>> import numpy as np
>>> memoryview(np.array([1, 2, 3], dtype='F')).format
'Zf'
>>> memoryview(np.array([1, 2, 3], dtype='D')).format
'Zd'

So I propose adding support for Zd and Zf formats in array, ctypes, memoryview and struct. It requires changing the code expecting a single character to now accept a string (Zd and Zf have 2 characters!).

Linked PRs

• gh-148675: Add Zd/Zf formats to array, ctypes, memoryview, struct #148676
• gh-148675: Revert GH-146237 and GH-146241 #148674
• gh-148675: Remove F and D formats from array and memoryview #149368
• gh-148675: Optimize arraydescr structure: use char[3] #149455
• gh-148675: Use a string for ctypes cparam tag #149778
• gh-148675: Reuse typecodes for array.array() error message #149779
• [3.15] gh-148675: Use a string for ctypes cparam tag (GH-149778) #149869