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| -rw-r--r-- | Doc/api/concrete.tex | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/Doc/api/concrete.tex b/Doc/api/concrete.tex index 53c3b67..6079a93 100644 --- a/Doc/api/concrete.tex +++ b/Doc/api/concrete.tex @@ -787,14 +787,24 @@ These are the basic Unicode object types used for the Unicode implementation in Python: \begin{ctypedesc}{Py_UNICODE} - This type represents a 16-bit unsigned storage type which is used by - Python internally as basis for holding Unicode ordinals. On - platforms where \ctype{wchar_t} is available and also has 16-bits, - \ctype{Py_UNICODE} is a typedef alias for \ctype{wchar_t} to enhance - native platform compatibility. On all other platforms, - \ctype{Py_UNICODE} is a typedef alias for \ctype{unsigned short}. + This type represents the storage type which is used by Python + internally as basis for holding Unicode ordinals. Python's default + builds use a 16-bit type for \ctype{Py_UNICODE} and store Unicode + values internally as UCS2. It is also possible to build a UCS4 + version of Python (most recent Linux distributions come with UCS4 + builds of Python). These builds then use a 32-bit type for + \ctype{Py_UNICODE} and store Unicode data internally as UCS4. On + platforms where \ctype{wchar_t} is available and compatible with the + chosen Python Unicode build variant, \ctype{Py_UNICODE} is a typedef + alias for \ctype{wchar_t} to enhance native platform compatibility. + On all other platforms, \ctype{Py_UNICODE} is a typedef alias for + either \ctype{unsigned short} (UCS2) or \ctype{unsigned long} + (UCS4). \end{ctypedesc} +Note that UCS2 and UCS4 Python builds are not binary compatible. +Please keep this in mind when writing extensions or interfaces. + \begin{ctypedesc}{PyUnicodeObject} This subtype of \ctype{PyObject} represents a Python Unicode object. \end{ctypedesc} |