# Finishing the Great Renaming

**URL:** <https://discuss.python.org/t/finishing-the-great-renaming/54082>\
**Category:** C API\
**Created:** [May 23, 2024, 8:46pm UTC](https://discuss.python.org/t/finishing-the-great-renaming/54082 "2024-05-23T20:46:56Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![encukou](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/encukou/32/2461_2.png) [@encukou](https://discuss.python.org/u/encukou)\
**Post date:** [May 23, 2024, 8:46pm UTC](https://discuss.python.org/t/finishing-the-great-renaming/54082/1 "2024-05-23T20:46:56Z")

</div>

Long ago in Python 1, there was a “Great Renaming” – adding `Py` prefixes to all names in the C API, so that the names don’t clash with other code, especially if Python is embedded.  
[Guido’s 2009 blog post about it](https://python-history.blogspot.com/2009/03/great-or-grand-renaming.html) has aged very well; read it for more details and rationale (and a nice plan to maintain backwards-compatibility).

But, the renaming wasn’t done for all API: many macros, typedefs and struct tags are still unprefixed. Sometimes new ones are added, either by mistake or for consistency with existing ones (see [#118771](https://github.com/python/cpython/issues/118771) for recent ones).  
Sometimes a clash is found in real-world code, reported and fixed (e.g. [#118207](https://github.com/python/cpython/issues/118207)); but I worry that some users will silently work around clashes rather than report them, especially if they’re slow to adopt a new Python version.

I’d like to have some plan about what to do here.  
Obviously, we need to be very careful about backwards compatibility; I expect we’ll want to document intentional exceptions, and avoid new ones, more than remove existing API.

I have some opinions, but I’d be interested in brainstorming and hearing what you think :‍)

Here are some things we could do:

- Add checks to avoid adding more unprefixed names (extending `make smelly` to macros & types)
- Document our naming convention, and any intentional exceptions to it
- Provide prefixed alternatives using e.g. `typedef` or `#define`, and encourage linters & foreign-language wrappers to use those
- Add an opt-in that disables the unprefixed names, so people writing new code don’t need to worry about clashes (for example, [PEP 743](https://peps.python.org/pep-0743/))

* * *

And here’s the list of unprefixed names I found.  
We’ll probably need different strategies for different cases:

> **(click to expand)**
>
> ### Typedefs for function pointers:
> 
> `getter`, `setter` and `destructor` are probably the most generic  
> names Python defines.
> 
> `getter` (descrobject.h)  
> `setter` (descrobject.h)  
> `getbufferproc` (pybuffer.h)  
> `wrapperfunc` (cpython/descrobject.h)  
> `wrapperfunc_kwds` (cpython/descrobject.h)  
> `gcvisitobjects_t` (objimpl.h)  
> `atexit_datacallbackfunc` (cpython/pylifecycle.h)  
> `sendfunc` (cpython/object.h)
> 
> Most function typedefs are for type slots in object.h:
> 
> `allocfunc`  
> `binaryfunc`  
> `descrgetfunc`  
> `descrsetfunc`  
> `destructor`  
> `freefunc`  
> `getattrfunc`  
> `getattrofunc`  
> `getiterfunc`  
> `hashfunc`  
> `initproc`  
> `inquiry`  
> `iternextfunc`  
> `lenfunc`  
> `newfunc`  
> `objobjargproc`  
> `objobjproc`  
> `printfunc`  
> `releasebufferproc`  
> `reprfunc`  
> `richcmpfunc`  
> `setattrfunc`  
> `setattrofunc`  
> `ssizeargfunc`  
> `ssizeobjargproc`  
> `ssizessizeargfunc`  
> `ssizessizeobjargproc`  
> `ternaryfunc`  
> `traverseproc`  
> `unaryfunc`  
> `vectorcallfunc`  
> `visitproc`
> 
> ### Struct tags & typedefs
> 
> Various structs:
> 
> `setentry` (cpython/setobject.h)  
> `struct setentry` (cpython/setobject.h)  
> `struct wrapperbase` (cpython/descrobject.h)  
> `PerfMapState` (sysmodule.h)  
> `struct PerfMapState` (sysmodule.h)
> 
> Simple typedefs:
> 
> `digit` (cpython/longintrepr.h)  
> `sdigit` (cpython/longintrepr.h)  
> `twodigits` (cpython/longintrepr.h)  
> `stwodigits` (cpython/longintrepr.h)
> 
> Names starting with `_py`:
> 
> `_py_make_codeunit` (cpython/code.h)  
> `_py_set_opcode` (cpython/code.h)  
> `struct _pycontextobject` (cpython/context.h)  
> `struct _pycontexttokenobject` (cpython/context.h)  
> `struct _pycontextvarobject` (cpython/context.h)
> 
> Other underscore-prefixed struct tags:
> 
> `struct _dictvalues` (cpython/dictobject.h)  
> `struct _err_stackitem` (cpython/pystate.h)  
> `struct _frame` (pytypedefs.h)  
> `struct _frozen` (cpython/import.h)  
> `struct _heaptypeobject` (cpython/object.h)  
> `struct _inittab` (cpython/import.h)  
> `struct _is` (pytypedefs.h)  
> `struct _line_offsets` (cpython/code.h)  
> `struct _longobject` (cpython/longintrepr.h)  
> `struct _object` (object.h)  
> `struct _odictobject` (cpython/odictobject.h)  
> `struct _opaque` (cpython/code.h)  
> `struct _specialization_cache` (cpython/object.h)  
> `struct _stack_chunk` (cpython/pystate.h)  
> `struct _traceback` (cpython/traceback.h)  
> `struct _ts` (cpython/pystate.h)  
> `struct _typeobject` (cpython/object.h)
> 
> ### Undefined macro
> 
> Undefined after use. It should be safe to add the `_Py` prefix right now; I’ll do that if there are no objections.
> 
> `NATIVE_TSS_KEY_T` (cpython/pythread.h)
> 
> ### Macro families with their own prefixes
> 
> `CO_ASYNC_GENERATOR` (cpython/code.h)  
> `CO_COROUTINE` (cpython/code.h)  
> `CO_FUTURE_ABSOLUTE_IMPORT` (cpython/code.h)  
> `CO_FUTURE_ANNOTATIONS` (cpython/code.h)  
> `CO_FUTURE_BARRY_AS_BDFL` (cpython/code.h)  
> `CO_FUTURE_DIVISION` (cpython/code.h)  
> `CO_FUTURE_GENERATOR_STOP` (cpython/code.h)  
> `CO_FUTURE_PRINT_FUNCTION` (cpython/code.h)  
> `CO_FUTURE_UNICODE_LITERALS` (cpython/code.h)  
> `CO_FUTURE_WITH_STATEMENT` (cpython/code.h)  
> `CO_GENERATOR` (cpython/code.h)  
> `CO_ITERABLE_COROUTINE` (cpython/code.h)  
> `CO_MAXBLOCKS` (cpython/code.h)  
> `CO_NESTED` (cpython/code.h)  
> `CO_NEWLOCALS` (cpython/code.h)  
> `CO_NO_MONITORING_EVENTS` ([new in 3.13](https://github.com/python/cpython/issues/118771))  
> `CO_OPTIMIZED` (cpython/code.h)  
> `CO_VARARGS` (cpython/code.h)  
> `CO_VARKEYWORDS` (cpython/code.h)
> 
> `FUTURE_ABSOLUTE_IMPORT` (cpython/compile.h)  
> `FUTURE_ANNOTATIONS` (cpython/compile.h)  
> `FUTURE_BARRY_AS_BDFL` (cpython/compile.h)  
> `FUTURE_DIVISION` (cpython/compile.h)  
> `FUTURE_GENERATORS` (cpython/compile.h)  
> `FUTURE_GENERATOR_STOP` (cpython/compile.h)  
> `FUTURE_NESTED_SCOPES` (cpython/compile.h)  
> `FUTURE_PRINT_FUNCTION` (cpython/compile.h)  
> `FUTURE_UNICODE_LITERALS` (cpython/compile.h)  
> `FUTURE_WITH_STATEMENT` (cpython/compile.h)
> 
> `FVC_ASCII` (ceval.h)  
> `FVC_MASK` (ceval.h)  
> `FVC_NONE` (ceval.h)  
> `FVC_REPR` (ceval.h)  
> `FVC_STR` (ceval.h)  
> `FVS_HAVE_SPEC` (ceval.h)  
> `FVS_MASK` (ceval.h)
> 
> `METH_CLASS`  
> `METH_COEXIST`  
> `METH_FASTCALL`  
> `METH_KEYWORDS`  
> `METH_METHOD`  
> `METH_NOARGS`  
> `METH_O`  
> `METH_STACKLESS`  
> `METH_STATIC`  
> `METH_VARARGS`
> 
> `SSTATE_INTERNED_IMMORTAL` (cpython/unicodeobject.h)  
> `SSTATE_INTERNED_IMMORTAL_STATIC` (cpython/unicodeobject.h)  
> `SSTATE_INTERNED_MORTAL` (cpython/unicodeobject.h)  
> `SSTATE_NOT_INTERNED` (cpython/unicodeobject.h)
> 
> ### Assorted value macros
> 
> `MAX_CO_EXTRA_USERS` (pystate.h)  
> `TYPE_MAX_WATCHERS` (cpython/object.h)  
> `WAIT_LOCK` (pythread.h)  
> `NOWAIT_LOCK` (pythread.h)
> 
> ### Various configure macros (pyconfig.h, pyport.h)
> 
> On my system, I get several free-form macros, some of which are unused:
> 
> `DOUBLE_IS_LITTLE_ENDIAN_IEEE754`  
> `ENABLE_IPV6`  
> `MAJOR_IN_SYSMACROS`  
> `MVWDELCH_IS_EXPRESSION`  
> `PTHREAD_KEY_T_IS_COMPATIBLE_WITH_INT`  
> `RETSIGTYPE`  
> `SIGNED_RIGHT_SHIFT_ZERO_FILLS`  
> `STDC_HEADERS`  
> `SYS_SELECT_WITH_SYS_TIME`
> 
> There are many `ALIGNOF_` and `SIZEOF_*`; some of these are unused in CPyton,  
> others (but not all) could be replaced by C11 features:
> 
> `ALIGNOF_LONG`  
> `ALIGNOF_MAX_ALIGN_T`  
> `ALIGNOF_SIZE_T`  
> `SIZEOF_DOUBLE`  
> `SIZEOF_FLOAT`  
> `SIZEOF_FPOS_T`  
> `SIZEOF_INT`  
> `SIZEOF_LONG`  
> `SIZEOF_LONG_DOUBLE`  
> `SIZEOF_LONG_LONG`  
> `SIZEOF_OFF_T`  
> `SIZEOF_PID_T`  
> `SIZEOF_PTHREAD_KEY_T`  
> `SIZEOF_PTHREAD_T`  
> `SIZEOF_PY_HASH_T`  
> `SIZEOF_PY_UHASH_T`  
> `SIZEOF_SHORT`  
> `SIZEOF_SIZE_T`  
> `SIZEOF_TIME_T`  
> `SIZEOF_UINTPTR_T`  
> `SIZEOF_VOID_P`  
> `SIZEOF_WCHAR_T`  
> `SIZEOF__BOOL`
> 
> Several `WITH_*` used for Python features:
> 
> `WITH_DECIMAL_CONTEXTVAR`  
> `WITH_DOC_STRINGS`  
> `WITH_FREELISTS`  
> `WITH_PYMALLOC`  
> `WITH_THREAD`
> 
> and around 400 `HAVE_*` macros:
> 
> > **(click for the list)**
> >
> > `HAVE_ACCEPT`  
> > `HAVE_ACCEPT4`  
> > `HAVE_ACOSH`  
> > `HAVE_ADDRINFO`  
> > `HAVE_ALARM`  
> > `HAVE_ALLOCA_H`  
> > `HAVE_ASINH`  
> > `HAVE_ASM_TYPES_H`  
> > `HAVE_ATANH`  
> > `HAVE_BIND`  
> > `HAVE_BIND_TEXTDOMAIN_CODESET`  
> > `HAVE_BLUETOOTH_BLUETOOTH_H`  
> > `HAVE_BUILTIN_ATOMIC`  
> > `HAVE_CHMOD`  
> > `HAVE_CHOWN`  
> > `HAVE_CHROOT`  
> > `HAVE_CLOCK`  
> > `HAVE_CLOCK_GETRES`  
> > `HAVE_CLOCK_GETTIME`  
> > `HAVE_CLOCK_NANOSLEEP`  
> > `HAVE_CLOCK_SETTIME`  
> > `HAVE_CLOSE_RANGE`  
> > `HAVE_COMPUTED_GOTOS`  
> > `HAVE_CONFSTR`  
> > `HAVE_CONNECT`  
> > `HAVE_COPY_FILE_RANGE`  
> > `HAVE_CTERMID`  
> > `HAVE_CURSES_FILTER`  
> > `HAVE_CURSES_H`  
> > `HAVE_CURSES_HAS_KEY`  
> > `HAVE_CURSES_IMMEDOK`  
> > `HAVE_CURSES_IS_PAD`  
> > `HAVE_CURSES_IS_TERM_RESIZED`  
> > `HAVE_CURSES_RESIZETERM`  
> > `HAVE_CURSES_RESIZE_TERM`  
> > `HAVE_CURSES_SYNCOK`  
> > `HAVE_CURSES_TYPEAHEAD`  
> > `HAVE_CURSES_USE_ENV`  
> > `HAVE_CURSES_WCHGAT`  
> > `HAVE_DECL_RTLD_DEEPBIND`  
> > `HAVE_DECL_RTLD_GLOBAL`  
> > `HAVE_DECL_RTLD_LAZY`  
> > `HAVE_DECL_RTLD_LOCAL`  
> > `HAVE_DECL_RTLD_MEMBER`  
> > `HAVE_DECL_RTLD_NODELETE`  
> > `HAVE_DECL_RTLD_NOLOAD`  
> > `HAVE_DECL_RTLD_NOW`  
> > `HAVE_DEVICE_MACROS`  
> > `HAVE_DEV_PTMX`  
> > `HAVE_DIRENT_D_TYPE`  
> > `HAVE_DIRENT_H`  
> > `HAVE_DIRFD`  
> > `HAVE_DLFCN_H`  
> > `HAVE_DLOPEN`  
> > `HAVE_DUP`  
> > `HAVE_DUP2`  
> > `HAVE_DUP3`  
> > `HAVE_DYNAMIC_LOADING`  
> > `HAVE_ENDIAN_H`  
> > `HAVE_EPOLL`  
> > `HAVE_EPOLL_CREATE1`  
> > `HAVE_ERF`  
> > `HAVE_ERFC`  
> > `HAVE_ERRNO_H`  
> > `HAVE_EVENTFD`  
> > `HAVE_EXECV`  
> > `HAVE_EXPLICIT_BZERO`  
> > `HAVE_EXPM1`  
> > `HAVE_FACCESSAT`  
> > `HAVE_FCHDIR`  
> > `HAVE_FCHMOD`  
> > `HAVE_FCHMODAT`  
> > `HAVE_FCHOWN`  
> > `HAVE_FCHOWNAT`  
> > `HAVE_FCNTL_H`  
> > `HAVE_FDATASYNC`  
> > `HAVE_FDOPENDIR`  
> > `HAVE_FEXECVE`  
> > `HAVE_FFI_CLOSURE_ALLOC`  
> > `HAVE_FFI_PREP_CIF_VAR`  
> > `HAVE_FFI_PREP_CLOSURE_LOC`  
> > `HAVE_FLOCK`  
> > `HAVE_FORK`  
> > `HAVE_FORKPTY`  
> > `HAVE_FPATHCONF`  
> > `HAVE_FSEEKO`  
> > `HAVE_FSTATAT`  
> > `HAVE_FSTATVFS`  
> > `HAVE_FSYNC`  
> > `HAVE_FTELLO`  
> > `HAVE_FTIME`  
> > `HAVE_FTRUNCATE`  
> > `HAVE_FUTIMENS`  
> > `HAVE_FUTIMES`  
> > `HAVE_FUTIMESAT`  
> > `HAVE_GAI_STRERROR`  
> > `HAVE_GCC_ASM_FOR_X64`  
> > `HAVE_GCC_ASM_FOR_X87`  
> > `HAVE_GCC_UINT128_T`  
> > `HAVE_GDBM_H`  
> > `HAVE_GDBM_NDBM_H`  
> > `HAVE_GETADDRINFO`  
> > `HAVE_GETC_UNLOCKED`  
> > `HAVE_GETEGID`  
> > `HAVE_GETENTROPY`  
> > `HAVE_GETEUID`  
> > `HAVE_GETGID`  
> > `HAVE_GETGRGID`  
> > `HAVE_GETGRGID_R`  
> > `HAVE_GETGRNAM_R`  
> > `HAVE_GETGROUPLIST`  
> > `HAVE_GETGROUPS`  
> > `HAVE_GETHOSTBYADDR`  
> > `HAVE_GETHOSTBYNAME`  
> > `HAVE_GETHOSTBYNAME_R`  
> > `HAVE_GETHOSTBYNAME_R_6_ARG`  
> > `HAVE_GETHOSTNAME`  
> > `HAVE_GETITIMER`  
> > `HAVE_GETLOADAVG`  
> > `HAVE_GETLOGIN`  
> > `HAVE_GETNAMEINFO`  
> > `HAVE_GETPAGESIZE`  
> > `HAVE_GETPEERNAME`  
> > `HAVE_GETPGID`  
> > `HAVE_GETPGRP`  
> > `HAVE_GETPID`  
> > `HAVE_GETPPID`  
> > `HAVE_GETPRIORITY`  
> > `HAVE_GETPROTOBYNAME`  
> > `HAVE_GETPWENT`  
> > `HAVE_GETPWNAM_R`  
> > `HAVE_GETPWUID`  
> > `HAVE_GETPWUID_R`  
> > `HAVE_GETRANDOM`  
> > `HAVE_GETRANDOM_SYSCALL`  
> > `HAVE_GETRESGID`  
> > `HAVE_GETRESUID`  
> > `HAVE_GETRUSAGE`  
> > `HAVE_GETSERVBYNAME`  
> > `HAVE_GETSERVBYPORT`  
> > `HAVE_GETSID`  
> > `HAVE_GETSOCKNAME`  
> > `HAVE_GETSPENT`  
> > `HAVE_GETSPNAM`  
> > `HAVE_GETUID`  
> > `HAVE_GETWD`  
> > `HAVE_GRP_H`  
> > `HAVE_HSTRERROR`  
> > `HAVE_HTOLE64`  
> > `HAVE_IF_NAMEINDEX`  
> > `HAVE_INET_ATON`  
> > `HAVE_INET_NTOA`  
> > `HAVE_INET_PTON`  
> > `HAVE_INITGROUPS`  
> > `HAVE_INTTYPES_H`  
> > `HAVE_KILL`  
> > `HAVE_KILLPG`  
> > `HAVE_LANGINFO_H`  
> > `HAVE_LCHOWN`  
> > `HAVE_LIBB2`  
> > `HAVE_LIBDL`  
> > `HAVE_LIBINTL_H`  
> > `HAVE_LIBSQLITE3`  
> > `HAVE_LINK`  
> > `HAVE_LINKAT`  
> > `HAVE_LINUX_AUXVEC_H`  
> > `HAVE_LINUX_CAN_BCM_H`  
> > `HAVE_LINUX_CAN_H`  
> > `HAVE_LINUX_CAN_J1939_H`  
> > `HAVE_LINUX_CAN_RAW_FD_FRAMES`  
> > `HAVE_LINUX_CAN_RAW_H`  
> > `HAVE_LINUX_CAN_RAW_JOIN_FILTERS`  
> > `HAVE_LINUX_FS_H`  
> > `HAVE_LINUX_LIMITS_H`  
> > `HAVE_LINUX_MEMFD_H`  
> > `HAVE_LINUX_NETLINK_H`  
> > `HAVE_LINUX_QRTR_H`  
> > `HAVE_LINUX_RANDOM_H`  
> > `HAVE_LINUX_SOUNDCARD_H`  
> > `HAVE_LINUX_TIPC_H`  
> > `HAVE_LINUX_VM_SOCKETS_H`  
> > `HAVE_LINUX_WAIT_H`  
> > `HAVE_LISTEN`  
> > `HAVE_LOCKF`  
> > `HAVE_LOG1P`  
> > `HAVE_LOG2`  
> > `HAVE_LOGIN_TTY`  
> > `HAVE_LONG_DOUBLE`  
> > `HAVE_LONG_LONG`  
> > `HAVE_LSTAT`  
> > `HAVE_LUTIMES`  
> > `HAVE_MADVISE`  
> > `HAVE_MAKEDEV`  
> > `HAVE_MBRTOWC`  
> > `HAVE_MEMFD_CREATE`  
> > `HAVE_MEMRCHR`  
> > `HAVE_MKDIRAT`  
> > `HAVE_MKFIFO`  
> > `HAVE_MKFIFOAT`  
> > `HAVE_MKNOD`  
> > `HAVE_MKNODAT`  
> > `HAVE_MKTIME`  
> > `HAVE_MMAP`  
> > `HAVE_MREMAP`  
> > `HAVE_NANOSLEEP`  
> > `HAVE_NCURSESW`  
> > `HAVE_NCURSES_H`  
> > `HAVE_NDBM_H`  
> > `HAVE_NETDB_H`  
> > `HAVE_NETINET_IN_H`  
> > `HAVE_NETPACKET_PACKET_H`  
> > `HAVE_NET_ETHERNET_H`  
> > `HAVE_NET_IF_H`  
> > `HAVE_NICE`  
> > `HAVE_OPENAT`  
> > `HAVE_OPENDIR`  
> > `HAVE_OPENPTY`  
> > `HAVE_PANEL_H`  
> > `HAVE_PATHCONF`  
> > `HAVE_PAUSE`  
> > `HAVE_PIPE`  
> > `HAVE_PIPE2`  
> > `HAVE_POLL`  
> > `HAVE_POLL_H`  
> > `HAVE_POSIX_FADVISE`  
> > `HAVE_POSIX_FALLOCATE`  
> > `HAVE_POSIX_SPAWN`  
> > `HAVE_POSIX_SPAWNP`  
> > `HAVE_PREAD`  
> > `HAVE_PREADV`  
> > `HAVE_PREADV2`  
> > `HAVE_PRLIMIT`  
> > `HAVE_PROTOTYPES`  
> > `HAVE_PTHREAD_CONDATTR_SETCLOCK`  
> > `HAVE_PTHREAD_GETCPUCLOCKID`  
> > `HAVE_PTHREAD_H`  
> > `HAVE_PTHREAD_KILL`  
> > `HAVE_PTHREAD_SIGMASK`  
> > `HAVE_PTY_H`  
> > `HAVE_PWRITE`  
> > `HAVE_PWRITEV`  
> > `HAVE_PWRITEV2`  
> > `HAVE_READLINK`  
> > `HAVE_READLINKAT`  
> > `HAVE_READV`  
> > `HAVE_REALPATH`  
> > `HAVE_RECVFROM`  
> > `HAVE_RENAMEAT`  
> > `HAVE_RL_APPEND_HISTORY`  
> > `HAVE_RL_CATCH_SIGNAL`  
> > `HAVE_RL_COMPDISP_FUNC_T`  
> > `HAVE_RL_COMPLETION_APPEND_CHARACTER`  
> > `HAVE_RL_COMPLETION_DISPLAY_MATCHES_HOOK`  
> > `HAVE_RL_COMPLETION_MATCHES`  
> > `HAVE_RL_COMPLETION_SUPPRESS_APPEND`  
> > `HAVE_RL_PRE_INPUT_HOOK`  
> > `HAVE_RL_RESIZE_TERMINAL`  
> > `HAVE_SCHED_GET_PRIORITY_MAX`  
> > `HAVE_SCHED_H`  
> > `HAVE_SCHED_RR_GET_INTERVAL`  
> > `HAVE_SCHED_SETAFFINITY`  
> > `HAVE_SCHED_SETPARAM`  
> > `HAVE_SCHED_SETSCHEDULER`  
> > `HAVE_SEM_CLOCKWAIT`  
> > `HAVE_SEM_GETVALUE`  
> > `HAVE_SEM_OPEN`  
> > `HAVE_SEM_TIMEDWAIT`  
> > `HAVE_SEM_UNLINK`  
> > `HAVE_SENDFILE`  
> > `HAVE_SENDTO`  
> > `HAVE_SETEGID`  
> > `HAVE_SETEUID`  
> > `HAVE_SETGID`  
> > `HAVE_SETGROUPS`  
> > `HAVE_SETHOSTNAME`  
> > `HAVE_SETITIMER`  
> > `HAVE_SETJMP_H`  
> > `HAVE_SETLOCALE`  
> > `HAVE_SETNS`  
> > `HAVE_SETPGID`  
> > `HAVE_SETPGRP`  
> > `HAVE_SETPRIORITY`  
> > `HAVE_SETREGID`  
> > `HAVE_SETRESGID`  
> > `HAVE_SETRESUID`  
> > `HAVE_SETREUID`  
> > `HAVE_SETSID`  
> > `HAVE_SETSOCKOPT`  
> > `HAVE_SETUID`  
> > `HAVE_SETVBUF`  
> > `HAVE_SHADOW_H`  
> > `HAVE_SHM_OPEN`  
> > `HAVE_SHM_UNLINK`  
> > `HAVE_SHUTDOWN`  
> > `HAVE_SIGACTION`  
> > `HAVE_SIGALTSTACK`  
> > `HAVE_SIGFILLSET`  
> > `HAVE_SIGINFO_T_SI_BAND`  
> > `HAVE_SIGINTERRUPT`  
> > `HAVE_SIGNAL_H`  
> > `HAVE_SIGPENDING`  
> > `HAVE_SIGRELSE`  
> > `HAVE_SIGTIMEDWAIT`  
> > `HAVE_SIGWAIT`  
> > `HAVE_SIGWAITINFO`  
> > `HAVE_SNPRINTF`  
> > `HAVE_SOCKADDR_ALG`  
> > `HAVE_SOCKADDR_STORAGE`  
> > `HAVE_SOCKET`  
> > `HAVE_SOCKETPAIR`  
> > `HAVE_SPAWN_H`  
> > `HAVE_SPLICE`  
> > `HAVE_SSIZE_T`  
> > `HAVE_STATVFS`  
> > `HAVE_STAT_TV_NSEC`  
> > `HAVE_STDINT_H`  
> > `HAVE_STDIO_H`  
> > `HAVE_STDLIB_H`  
> > `HAVE_STD_ATOMIC`  
> > `HAVE_STRFTIME`  
> > `HAVE_STRINGS_H`  
> > `HAVE_STRING_H`  
> > `HAVE_STRLCPY`  
> > `HAVE_STRSIGNAL`  
> > `HAVE_STRUCT_PASSWD_PW_GECOS`  
> > `HAVE_STRUCT_PASSWD_PW_PASSWD`  
> > `HAVE_STRUCT_STAT_ST_BLKSIZE`  
> > `HAVE_STRUCT_STAT_ST_BLOCKS`  
> > `HAVE_STRUCT_STAT_ST_RDEV`  
> > `HAVE_STRUCT_TM_TM_ZONE`  
> > `HAVE_SYMLINK`  
> > `HAVE_SYMLINKAT`  
> > `HAVE_SYNC`  
> > `HAVE_SYSCONF`  
> > `HAVE_SYSEXITS_H`  
> > `HAVE_SYSLOG_H`  
> > `HAVE_SYSTEM`  
> > `HAVE_SYS_AUXV_H`  
> > `HAVE_SYS_EPOLL_H`  
> > `HAVE_SYS_EVENTFD_H`  
> > `HAVE_SYS_FILE_H`  
> > `HAVE_SYS_IOCTL_H`  
> > `HAVE_SYS_MMAN_H`  
> > `HAVE_SYS_PARAM_H`  
> > `HAVE_SYS_POLL_H`  
> > `HAVE_SYS_RANDOM_H`  
> > `HAVE_SYS_RESOURCE_H`  
> > `HAVE_SYS_SELECT_H`  
> > `HAVE_SYS_SENDFILE_H`  
> > `HAVE_SYS_SOCKET_H`  
> > `HAVE_SYS_SOUNDCARD_H`  
> > `HAVE_SYS_STATVFS_H`  
> > `HAVE_SYS_STAT_H`  
> > `HAVE_SYS_SYSCALL_H`  
> > `HAVE_SYS_SYSMACROS_H`  
> > `HAVE_SYS_TIMES_H`  
> > `HAVE_SYS_TIME_H`  
> > `HAVE_SYS_TYPES_H`  
> > `HAVE_SYS_UIO_H`  
> > `HAVE_SYS_UN_H`  
> > `HAVE_SYS_UTSNAME_H`  
> > `HAVE_SYS_WAIT_H`  
> > `HAVE_SYS_XATTR_H`  
> > `HAVE_TCGETPGRP`  
> > `HAVE_TCSETPGRP`  
> > `HAVE_TEMPNAM`  
> > `HAVE_TERMIOS_H`  
> > `HAVE_TERM_H`  
> > `HAVE_TIMEGM`  
> > `HAVE_TIMES`  
> > `HAVE_TMPFILE`  
> > `HAVE_TMPNAM`  
> > `HAVE_TMPNAM_R`  
> > `HAVE_TM_ZONE`  
> > `HAVE_TRUNCATE`  
> > `HAVE_TTYNAME`  
> > `HAVE_UMASK`  
> > `HAVE_UNAME`  
> > `HAVE_UNISTD_H`  
> > `HAVE_UNLINKAT`  
> > `HAVE_UNSHARE`  
> > `HAVE_USABLE_WCHAR_T`  
> > `HAVE_UTIMENSAT`  
> > `HAVE_UTIMES`  
> > `HAVE_UTIME_H`  
> > `HAVE_UTMP_H`  
> > `HAVE_UUID_GENERATE_TIME_SAFE`  
> > `HAVE_UUID_H`  
> > `HAVE_VFORK`  
> > `HAVE_WAIT`  
> > `HAVE_WAIT3`  
> > `HAVE_WAIT4`  
> > `HAVE_WAITID`  
> > `HAVE_WAITPID`  
> > `HAVE_WCHAR_H`  
> > `HAVE_WCSCOLL`  
> > `HAVE_WCSFTIME`  
> > `HAVE_WCSXFRM`  
> > `HAVE_WMEMCMP`  
> > `HAVE_WORKING_TZSET`  
> > `HAVE_WRITEV`  
> > `HAVE_ZLIB_COPY`

---

<div class="post-metadata">

**Author:** ![vstinner](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/vstinner/32/15130_2.png) [@vstinner](https://discuss.python.org/u/vstinner)\
**Post date:** [May 23, 2024, 9:21pm UTC](https://discuss.python.org/t/finishing-the-great-renaming/54082/2 "2024-05-23T21:21:09Z")

</div>

> [@encukou](#):
>
> - Provide prefixed alternatives using e.g. `typedef` or `#define`, and encourage linters & foreign-language wrappers to use those
> - Add an opt-in that disables the unprefixed names, so people writing new code don’t need to worry about clashes (for example, [PEP 743](https://peps.python.org/pep-0743/))

It sounds like a good plan. I suggest to start by adding Py names, and keep old names as aliases to Py names. Later we can decide how to deal with old aliases.

---

<div class="post-metadata">

**Author:** ![guido](https://sea2.discourse-cdn.com/flex002/user_avatar/discuss.python.org/guido/32/21_2.png) [@guido](https://discuss.python.org/u/guido)\
**Post date:** [May 23, 2024, 10:19pm UTC](https://discuss.python.org/t/finishing-the-great-renaming/54082/3 "2024-05-23T22:19:07Z")

</div>

I agree that we need to do something here. I’d also like to make sure that developers understand _why_ we add `Py` prefixes (or `_Py` – where I write `Py` below I include this). Without such understanding we will see unnecessary `Py` prefixes which could confuse readers of the source code.

Python’s original grand renaming was almost exclusively concerned with link-level clashes, since those are virtually impossible to work around when they exist. If two unrelated libraries both define a global function named `getitem` there’s no (portable) way to use those libraries in the same program, even if they are used by different parts of the program, even if they are technically internal to each library.

The grand renaming didn’t concern itself much with names that only exist at compile time – notably macros, typedefs and struct tags, as Petr mentions – because the conditions required for those to cause a conflict only exist if a Python header file is included by some file that also includes a header file belonging to some other library or framework. Of course, this is much more likely today than it was in 1995, so it’s more than time to do something about it.

I still worry a bit about the requirement for `Py` prefixes to be mistakenly applied to contexts where it isn’t helpful. We already have a smattering of `Py`-prefixed `static` functions in C files. I find those confusing because as a reader encountering one of their uses I am led to believe that the definition might live elsewhere (as might other uses).

There are also some surprising issues around non-linker symbols defined in _internal_ headers. It appears those sometimes end up being included by applications or libraries/frameworks that prefer to break the rules in order to get performance (or sometimes just access to internal semantics), and there they occasionally conflict with symbols defined elsewhere. I prefer that we deal with those on a case-by-case basis rather than insisting that every _internal_ typedef (etc.) must also have a `Py` prefix.

But apart from those concerns, I agree we should do this!