cpython/Include/cpython/pyctype.h

#ifndef Py_LIMITED_API
#ifndef PYCTYPE_H
#define PYCTYPE_H
#ifdef __cplusplus
extern "C" {
#endif

#define PY_CTF_LOWER …
#define PY_CTF_UPPER …
#define PY_CTF_ALPHA …
#define PY_CTF_DIGIT …
#define PY_CTF_ALNUM …
#define PY_CTF_SPACE …
#define PY_CTF_XDIGIT …

PyAPI_DATA(const unsigned int) _Py_ctype_table[256];

/* Unlike their C counterparts, the following macros are not meant to
 * handle an int with any of the values [EOF, 0-UCHAR_MAX]. The argument
 * must be a signed/unsigned char. */
#define Py_ISLOWER(c) …
#define Py_ISUPPER(c) …
#define Py_ISALPHA(c) …
#define Py_ISDIGIT(c) …
#define Py_ISXDIGIT(c) …
#define Py_ISALNUM(c) …
#define Py_ISSPACE(c) …

PyAPI_DATA(const unsigned char) _Py_ctype_tolower[256];
PyAPI_DATA(const unsigned char) _Py_ctype_toupper[256];

#define Py_TOLOWER(c) …
#define Py_TOUPPER(c) …

#ifdef __cplusplus
}
#endif
#endif /* !PYCTYPE_H */
#endif /* !Py_LIMITED_API */