# Configuração de Inicialização do Python

Novo na versão 3.8.

Python pode ser inicializado com `Py_InitializeFromConfig()` e a estrutura `PyConfig`. Pode ser pré-inicializado com `Py_PreInitialize()` e a estrutura `PyPreConfig`.

Existem dois tipos de configuração:

- A Python Configuration pode ser usada para construir um Python personalizado que se comporta como um Python comum. Por exemplo, variáveis de ambiente e argumento de linha de comando são usados para configurar Python.

- A Configuração isolada pode ser usada para incorporar Python em uma aplicação. Isso isola Python de um sistema. Por exemplo, variáveis de ambiente são ignoradas, a variável local LC_CTYPE fica inalterada e nenhum manipulador de sinal é registrado.

A função `Py_RunMain()` pode ser usada para escrever um programa Python personalizado.

Veja também Inicialização, Finalização e Threads.

Ver também

PEP 587 “Configuração da inicialização do Python”.

## Exemplo

Exemplo de Python personalizado sendo executado sempre em um modo isolado:

    int main(int argc, char **argv)
    {
        PyStatus status;

        PyConfig config;
        PyConfig_InitPythonConfig(&config);
        config.isolated = 1;

        /* Decode command line arguments.
           Implicitly preinitialize Python (in isolated mode). */
        status = PyConfig_SetBytesArgv(&config, argc, argv);
        if (PyStatus_Exception(status)) {
            goto exception;
        }

        status = Py_InitializeFromConfig(&config);
        if (PyStatus_Exception(status)) {
            goto exception;
        }
        PyConfig_Clear(&config);

        return Py_RunMain();

    exception:
        PyConfig_Clear(&config);
        if (PyStatus_IsExit(status)) {
            return status.exitcode;
        }
        /* Display the error message and exit the process with
           non-zero exit code */
        Py_ExitStatusException(status);
    }

## PyWideStringList

type `PyWideStringList`

  Lista de strings `wchar_t*`.

  Se length é diferente de zero, items deve ser diferente de `NULL` e todas as strings devem ser diferentes de `NULL`.

  Métodos:

  PyStatus `PyWideStringList_Append`(PyWideStringList *list, const wchar_t *item)

    Anexa item a list.

    Python deve ser inicializado previamente antes de chamar essa função.

  PyStatus `PyWideStringList_Insert`(PyWideStringList *list, Py_ssize_t index, const wchar_t *item)

    Insere item na list na posição index.

    Se index for maior ou igual ao comprimento da list, anexa o item a list.

    index deve ser maior que ou igual a 0.

    Python deve ser inicializado previamente antes de chamar essa função.

  Campos de estrutura:

  Py_ssize_t `length`

    Comprimento da lista.

  wchar_t **`items`

    Itens da lista.

## PyStatus

type `PyStatus`

  Estrutura para armazenar o status de uma função de inicialização: sucesso, erro ou saída.

  Para um erro, ela pode armazenar o nome da função C que criou o erro.

  Campos de estrutura:

  int `exitcode`

    Código de saída. Argumento passado para `exit()`.

  const char *`err_msg`

    Mensagem de erro.

  const char *`func`

    Nome da função que criou um erro. Pode ser `NULL`.

  Funções para criar um status:

  PyStatus `PyStatus_Ok`(void)

    Sucesso.

  PyStatus `PyStatus_Error`(const char *err_msg)

    Erro de inicialização com uma mensagem.

    err_msg não deve ser `NULL`.

  PyStatus `PyStatus_NoMemory`(void)

    Falha de alocação de memória (sem memória).

  PyStatus `PyStatus_Exit`(int exitcode)

    Sai do Python com o código de saída especificado.

  Funções para manipular um status:

  int `PyStatus_Exception`(PyStatus status)

    O status é um erro ou uma saída? Se verdadeiro, a exceção deve ser tratada; chamando `Py_ExitStatusException()`, por exemplo.

  int `PyStatus_IsError`(PyStatus status)

    O resultado é um erro?

  int `PyStatus_IsExit`(PyStatus status)

    O resultado é uma saída?

  void `Py_ExitStatusException`(PyStatus status)

    Chama `exit(exitcode)` se status for uma saída. Exibe a mensagem de erro e sai com um código de saída diferente de zero se status for um erro. Deve ser chamado apenas se `PyStatus_Exception(status)` for diferente de zero.

Nota

Internamente, Python usa macros que definem `PyStatus.func`, enquanto funções para criar um status definem `func` para `NULL`.

Exemplo:

    PyStatus alloc(void **ptr, size_t size)
    {
        *ptr = PyMem_RawMalloc(size);
        if (*ptr == NULL) {
            return PyStatus_NoMemory();
        }
        return PyStatus_Ok();
    }

    int main(int argc, char **argv)
    {
        void *ptr;
        PyStatus status = alloc(&ptr, 16);
        if (PyStatus_Exception(status)) {
            Py_ExitStatusException(status);
        }
        PyMem_Free(ptr);
        return 0;
    }

## PyPreConfig

type `PyPreConfig`

  Estrutura usada para pré-inicializar o Python.

  A função para inicializar uma pré-configuração:

  void `PyPreConfig_InitPythonConfig`(PyPreConfig *preconfig)

    Inicializa a pré-configuração com Configuração do Python.

  void `PyPreConfig_InitIsolatedConfig`(PyPreConfig *preconfig)

    Inicializa a pré-configuração com Configuração isolada.

  Campos de estrutura:

  int `allocator`

    Nome de alocadores de memória em Python:

    - `PYMEM_ALLOCATOR_NOT_SET` (`0`): não altera os alocadores de memória (usa o padrão).

    - `PYMEM_ALLOCATOR_DEFAULT` (`1`): alocadores de memória padrão.

    - `PYMEM_ALLOCATOR_DEBUG` (`2`): alocadores de memória padrão com ganchos de depuração.

    - `PYMEM_ALLOCATOR_MALLOC` (`3`): usa `malloc()` da biblioteca C.

    - `PYMEM_ALLOCATOR_MALLOC_DEBUG` (`4`): força uso de `malloc()` com ganchos de depuração.

    - `PYMEM_ALLOCATOR_PYMALLOC` (`5`): alocador de memória do Python pymalloc.

    - `PYMEM_ALLOCATOR_PYMALLOC_DEBUG` (`6`): alocador de memória deo Python pymalloc com ganchos de depuração.

    `PYMEM_ALLOCATOR_PYMALLOC` e `PYMEM_ALLOCATOR_PYMALLOC_DEBUG` não são suportados se o Python estiver `configurado usando --without-pymalloc`.

    Veja Gerenciamento de memória.

    Padrão: `PYMEM_ALLOCATOR_NOT_SET`.

  int `configure_locale`

    Define a localidade LC_CTYPE para a localidade preferida do usuário.

    If equals to 0, set `coerce_c_locale` and `coerce_c_locale_warn` members to 0.

    Veja a codificação da localidade.

    Padrão: `1` na configuração do Python, `0` na configuração isolada.

  int `coerce_c_locale`

    If equals to 2, coerce the C locale.

    If equals to 1, read the LC_CTYPE locale to decide if it should be coerced.

    Veja a codificação da localidade.

    Padrão: `-1` na configuração do Python, `0` na configuração isolada.

  int `coerce_c_locale_warn`

    Se diferente de zero, emite um aviso se a localidade C for forçada.

    Padrão: `-1` na configuração do Python, `0` na configuração isolada.

  int `dev_mode`

    If non-zero, enables the Python Development Mode: see `PyConfig.dev_mode`.

    Padrão: `-1` no modo do Python, `0` no modo isolado.

  int `isolated`

    Modo isolado: veja `PyConfig.isolated`.

    Padrão: `0` no modo do Python, `1` no modo isolado.

  int `legacy_windows_fs_encoding`

    Se não zero:

    - Define `PyPreConfig.utf8_mode` para `0`,

    - Define `PyConfig.filesystem_encoding` para `"mbcs"`,

    - Define `PyConfig.filesystem_errors` para `"replace"`.

    Inicializado a partir do valor da variável de ambiente `PYTHONLEGACYWINDOWSFSENCODING`.

    Disponível apenas no Windows. A macro `#ifdef MS_WINDOWS` pode ser usada para código específico do Windows.

    Padrão: `0`.

  int `parse_argv`

    Se diferente de zero, `Py_PreInitializeFromArgs()` e `Py_PreInitializeFromBytesArgs()` analisam seu argumento `argv` da mesma forma que o Python regular analisa argumentos de linha de comando: veja Argumentos de linha de comando.

    Padrão: `1` na configuração do Python, `0` na configuração isolada.

  int `use_environment`

    Usar variáveis de ambiente? Veja `PyConfig.use_environment`.

    Padrão: `1` na configuração do Python e `0` na configuração isolada.

  int `utf8_mode`

    Se não zero, habilita o modo UTF-8 do Python.

    Set by the `-X utf8` command line option and the `PYTHONUTF8` environment variable.

    Padrão: `-1` na configuração do Python e `0` na configuração isolada.

## Pré-inicializar Python com PyPreConfig

A pré-inicialização do Python:

- Define os alocadores de memória Python (`PyPreConfig.allocator`)

- Configura a localidade LC_CTYPE (codificação da localidade)

- Define o Modo UTF-8 do Python (`PyPreConfig.utf8_mode`)

A pré-configuração atual (tipo `PyPreConfig`) é armazenada em `_PyRuntime.preconfig`.

Funções para pré-inicializar Python:

PyStatus `Py_PreInitialize`(const PyPreConfig *preconfig)

  Pré-inicializa o Python a partir da pré-configuração preconfig.

  preconfig não pode ser `NULL`..

PyStatus `Py_PreInitializeFromBytesArgs`(const PyPreConfig *preconfig, int argc, char *const *argv)

  Pré-inicializa o Python a partir da pré-configuração preconfig.

  Analisa argumentos de linha de comando argv (strings de bytes) se `parse_argv` de preconfig for diferente de zero.

  preconfig não pode ser `NULL`..

PyStatus `Py_PreInitializeFromArgs`(const PyPreConfig *preconfig, int argc, wchar_t *const *argv)

  Pré-inicializa o Python a partir da pré-configuração preconfig.

  Analisa argumentos de linha de comando argv (strings largas) se `parse_argv` de preconfig for diferente de zero.

  preconfig não pode ser `NULL`..

O chamador é responsável por manipular exceções (erro ou saída) usando `PyStatus_Exception()` e `Py_ExitStatusException()`.

Para configuração do Python (`PyPreConfig_InitPythonConfig()`), se o Python for inicializado com argumentos de linha de comando, os argumentos de linha de comando também devem ser passados para pré-inicializar o Python, pois eles têm um efeito na pré-configuração como codificações. Por exemplo, a opção de linha de comando `-X utf8` habilita o Modo UTF-8 do Python.

`PyMem_SetAllocator()` pode ser chamado depois de `Py_PreInitialize()` e antes de `Py_InitializeFromConfig()` para instalar um alocador de memória personalizado. Ele pode ser chamado antes de `Py_PreInitialize()` se `PyPreConfig.allocator` estiver definido como `PYMEM_ALLOCATOR_NOT_SET`.

Funções de alocação de memória do Python como `PyMem_RawMalloc()` não devem ser usadas antes da pré-inicialização do Python, enquanto chamar diretamente `malloc()` e `free()` é sempre seguro. `Py_DecodeLocale()` não deve ser chamado antes da pré-inicialização do Python.

Exemplo usando a pré-inicialização para habilitar o modo UTF-8 do Python.

    PyStatus status;
    PyPreConfig preconfig;
    PyPreConfig_InitPythonConfig(&preconfig);

    preconfig.utf8_mode = 1;

    status = Py_PreInitialize(&preconfig);
    if (PyStatus_Exception(status)) {
        Py_ExitStatusException(status);
    }

    /* at this point, Python speaks UTF-8 */

    Py_Initialize();
    /* ... use Python API here ... */
    Py_Finalize();

## PyConfig

type `PyConfig`

  Estrutura contendo a maioria dos parâmetros para configurar o Python.

  Ao terminar, a função `PyConfig_Clear()` deve ser usada para liberar a memória de configuração.

  Structure methods:

  void `PyConfig_InitPythonConfig`(PyConfig *config)

    Initialize configuration with the Python Configuration.

  void `PyConfig_InitIsolatedConfig`(PyConfig *config)

    Initialize configuration with the Isolated Configuration.

  PyStatus `PyConfig_SetString`(PyConfig *config, wchar_t *const *config_str, const wchar_t *str)

    Copy the wide character string str into `*config_str`.

    Preinitialize Python if needed.

  PyStatus `PyConfig_SetBytesString`(PyConfig *config, wchar_t *const *config_str, const char *str)

    Decode str using `Py_DecodeLocale()` and set the result into `*config_str`.

    Preinitialize Python if needed.

  PyStatus `PyConfig_SetArgv`(PyConfig *config, int argc, wchar_t *const *argv)

    Set command line arguments (`argv` member of config) from the argv list of wide character strings.

    Preinitialize Python if needed.

  PyStatus `PyConfig_SetBytesArgv`(PyConfig *config, int argc, char *const *argv)

    Set command line arguments (`argv` member of config) from the argv list of bytes strings. Decode bytes using `Py_DecodeLocale()`.

    Preinitialize Python if needed.

  PyStatus `PyConfig_SetWideStringList`(PyConfig *config, PyWideStringList *list, Py_ssize_t length, wchar_t **items)

    Set the list of wide strings list to length and items.

    Preinitialize Python if needed.

  PyStatus `PyConfig_Read`(PyConfig *config)

    Read all Python configuration.

    Fields which are already initialized are left unchanged.

    The `PyConfig_Read()` function only parses `PyConfig.argv` arguments once: `PyConfig.parse_argv` is set to `2` after arguments are parsed. Since Python arguments are strippped from `PyConfig.argv`, parsing arguments twice would parse the application options as Python options.

    Preinitialize Python if needed.

    Alterado na versão 3.10: The `PyConfig.argv` arguments are now only parsed once, `PyConfig.parse_argv` is set to `2` after arguments are parsed, and arguments are only parsed if `PyConfig.parse_argv` equals `1`.

  void `PyConfig_Clear`(PyConfig *config)

    Release configuration memory.

  Most `PyConfig` methods preinitialize Python if needed. In that case, the Python preinitialization configuration (`PyPreConfig`) in based on the `PyConfig`. If configuration fields which are in common with `PyPreConfig` are tuned, they must be set before calling a `PyConfig` method:

  - `PyConfig.dev_mode`

  - `PyConfig.isolated`

  - `PyConfig.parse_argv`

  - `PyConfig.use_environment`

  Moreover, if `PyConfig_SetArgv()` or `PyConfig_SetBytesArgv()` is used, this method must be called before other methods, since the preinitialization configuration depends on command line arguments (if `parse_argv` is non-zero).

  The caller of these methods is responsible to handle exceptions (error or exit) using `PyStatus_Exception()` and `Py_ExitStatusException()`.

  Campos de estrutura:

  PyWideStringList `argv`

    Command line arguments: `sys.argv`.

    Set `parse_argv` to `1` to parse `argv` the same way the regular Python parses Python command line arguments and then to strip Python arguments from `argv`.

    If `argv` is empty, an empty string is added to ensure that `sys.argv` always exists and is never empty.

    Padrão: `NULL`.

    See also the `orig_argv` member.

  wchar_t *`base_exec_prefix`

    `sys.base_exec_prefix`.

    Padrão: `NULL`.

    Part of the Python Path Configuration output.

  wchar_t *`base_executable`

    Python base executable: `sys._base_executable`.

    Set by the `__PYVENV_LAUNCHER__` environment variable.

    Set from `PyConfig.executable` if `NULL`.

    Padrão: `NULL`.

    Part of the Python Path Configuration output.

  wchar_t *`base_prefix`

    `sys.base_prefix`.

    Padrão: `NULL`.

    Part of the Python Path Configuration output.

  int `buffered_stdio`

    If equals to 0 and `configure_c_stdio` is non-zero, disable buffering on the C streams stdout and stderr.

    Set to 0 by the `-u` command line option and the `PYTHONUNBUFFERED` environment variable.

    stdin is always opened in buffered mode.

    Padrão: `1`.

  int `bytes_warning`

    If equals to 1, issue a warning when comparing `bytes` or `bytearray` with `str`, or comparing `bytes` with `int`.

    If equal or greater to 2, raise a `BytesWarning` exception in these cases.

    Incremented by the `-b` command line option.

    Padrão: `0`.

  int `warn_default_encoding`

    If non-zero, emit a `EncodingWarning` warning when `io.TextIOWrapper` uses its default encoding. See Ativar EncodingWarning for details.

    Padrão: `0`.

    Novo na versão 3.10.

  wchar_t *`check_hash_pycs_mode`

    Control the validation behavior of hash-based `.pyc` files: value of the `--check-hash-based-pycs` command line option.

    Valores válidos:

    - `L"always"`: Hash the source file for invalidation regardless of value of the ‘check_source’ flag.

    - `L"never"`: Assume that hash-based pycs always are valid.

    - `L"default"`: The ‘check_source’ flag in hash-based pycs determines invalidation.

    Default: `L"default"`.

    See also PEP 552 “Deterministic pycs”.

  int `configure_c_stdio`

    If non-zero, configure C standard streams:

    - On Windows, set the binary mode (`O_BINARY`) on stdin, stdout and stderr.

    - If `buffered_stdio` equals zero, disable buffering of stdin, stdout and stderr streams.

    - If `interactive` is non-zero, enable stream buffering on stdin and stdout (only stdout on Windows).

    Padrão: `1` na configuração do Python, `0` na configuração isolada.

  int `dev_mode`

    If non-zero, enable the Python Development Mode.

    Padrão: `-1` no modo do Python, `0` no modo isolado.

  int `dump_refs`

    Dump Python references?

    If non-zero, dump all objects which are still alive at exit.

    Set to `1` by the `PYTHONDUMPREFS` environment variable.

    Need a special build of Python with the `Py_TRACE_REFS` macro defined: see the `configure --with-trace-refs option`.

    Padrão: `0`.

  wchar_t *`exec_prefix`

    The site-specific directory prefix where the platform-dependent Python files are installed: `sys.exec_prefix`.

    Padrão: `NULL`.

    Part of the Python Path Configuration output.

  wchar_t *`executable`

    The absolute path of the executable binary for the Python interpreter: `sys.executable`.

    Padrão: `NULL`.

    Part of the Python Path Configuration output.

  int `faulthandler`

    Enable faulthandler?

    If non-zero, call `faulthandler.enable()` at startup.

    Set to `1` by `-X faulthandler` and the `PYTHONFAULTHANDLER` environment variable.

    Padrão: `-1` no modo do Python, `0` no modo isolado.

  wchar_t *`filesystem_encoding`

    Filesystem encoding: `sys.getfilesystemencoding()`.

    On macOS, Android and VxWorks: use `"utf-8"` by default.

    On Windows: use `"utf-8"` by default, or `"mbcs"` if `legacy_windows_fs_encoding` of `PyPreConfig` is non-zero.

    Default encoding on other platforms:

    - `"utf-8"` if `PyPreConfig.utf8_mode` is non-zero.

    - `"ascii"` if Python detects that `nl_langinfo(CODESET)` announces the ASCII encoding, whereas the `mbstowcs()` function decodes from a different encoding (usually Latin1).

    - `"utf-8"` if `nl_langinfo(CODESET)` returns an empty string.

    - Otherwise, use the locale encoding: `nl_langinfo(CODESET)` result.

    At Python startup, the encoding name is normalized to the Python codec name. For example, `"ANSI_X3.4-1968"` is replaced with `"ascii"`.

    See also the `filesystem_errors` member.

  wchar_t *`filesystem_errors`

    Filesystem error handler: `sys.getfilesystemencodeerrors()`.

    On Windows: use `"surrogatepass"` by default, or `"replace"` if `legacy_windows_fs_encoding` of `PyPreConfig` is non-zero.

    On other platforms: use `"surrogateescape"` by default.

    Supported error handlers:

    - `"strict"`

    - `"surrogateescape"`

    - `"surrogatepass"` (only supported with the UTF-8 encoding)

    See also the `filesystem_encoding` member.

  unsigned long `hash_seed`
  int `use_hash_seed`

    Randomized hash function seed.

    If `use_hash_seed` is zero, a seed is chosen randomly at Python startup, and `hash_seed` is ignored.

    Set by the `PYTHONHASHSEED` environment variable.

    Default use_hash_seed value: `-1` in Python mode, `0` in isolated mode.

  wchar_t *`home`

    Python home directory.

    If `Py_SetPythonHome()` has been called, use its argument if it is not `NULL`.

    Set by the `PYTHONHOME` environment variable.

    Padrão: `NULL`.

    Part of the Python Path Configuration input.

  int `import_time`

    If non-zero, profile import time.

    Set the `1` by the `-X importtime` option and the `PYTHONPROFILEIMPORTTIME` environment variable.

    Padrão: `0`.

  int `inspect`

    Enter interactive mode after executing a script or a command.

    If greater than 0, enable inspect: when a script is passed as first argument or the -c option is used, enter interactive mode after executing the script or the command, even when `sys.stdin` does not appear to be a terminal.

    Incremented by the `-i` command line option. Set to `1` if the `PYTHONINSPECT` environment variable is non-empty.

    Padrão: `0`.

  int `install_signal_handlers`

    Install Python signal handlers?

    Default: `1` in Python mode, `0` in isolated mode.

  int `interactive`

    If greater than 0, enable the interactive mode (REPL).

    Incremented by the `-i` command line option.

    Padrão: `0`.

  int `isolated`

    If greater than 0, enable isolated mode:

    - `sys.path` contains neither the script’s directory (computed from `argv[0]` or the current directory) nor the user’s site-packages directory.

    - Python REPL doesn’t import `readline` nor enable default readline configuration on interactive prompts.

    - Set `use_environment` and `user_site_directory` to 0.

    Padrão: `0` no modo do Python, `1` no modo isolado.

    Veja também `PyPreConfig.isolated`.

  int `legacy_windows_stdio`

    If non-zero, use `io.FileIO` instead of `io.WindowsConsoleIO` for `sys.stdin`, `sys.stdout` and `sys.stderr`.

    Definida como `1` se a variável de ambiente `PYTHONLEGACYWINDOWSSTDIO` estiver definida como uma string não vazia.

    Disponível apenas no Windows. A macro `#ifdef MS_WINDOWS` pode ser usada para código específico do Windows.

    Padrão: `0`.

    See also the PEP 528 (Change Windows console encoding to UTF-8).

  int `malloc_stats`

    If non-zero, dump statistics on Python pymalloc memory allocator at exit.

    Set to `1` by the `PYTHONMALLOCSTATS` environment variable.

    The option is ignored if Python is `configured using the --without-pymalloc option`.

    Padrão: `0`.

  wchar_t *`platlibdir`

    Platform library directory name: `sys.platlibdir`.

    Set by the `PYTHONPLATLIBDIR` environment variable.

    Default: value of the `PLATLIBDIR` macro which is set by the `configure --with-platlibdir option` (default: `"lib"`).

    Part of the Python Path Configuration input.

    Novo na versão 3.9.

  wchar_t *`pythonpath_env`

    Module search paths (`sys.path`) as a string separated by `DELIM` (`os.path.pathsep`).

    Set by the `PYTHONPATH` environment variable.

    Padrão: `NULL`.

    Part of the Python Path Configuration input.

  PyWideStringList `module_search_paths`
  int `module_search_paths_set`

    Module search paths: `sys.path`.

    If `module_search_paths_set` is equal to 0, the function calculating the Python Path Configuration overrides the `module_search_paths` and sets `module_search_paths_set` to `1`.

    Default: empty list (`module_search_paths`) and `0` (`module_search_paths_set`).

    Part of the Python Path Configuration output.

  int `optimization_level`

    Compilation optimization level:

    - `0`: Peephole optimizer, set `__debug__` to `True`.

    - `1`: Level 0, remove assertions, set `__debug__` to `False`.

    - `2`: Level 1, strip docstrings.

    Incremented by the `-O` command line option. Set to the `PYTHONOPTIMIZE` environment variable value.

    Padrão: `0`.

  PyWideStringList `orig_argv`

    The list of the original command line arguments passed to the Python executable: `sys.orig_argv`.

    If `orig_argv` list is empty and `argv` is not a list only containing an empty string, `PyConfig_Read()` copies `argv` into `orig_argv` before modifying `argv` (if `parse_argv` is non-zero).

    See also the `argv` member and the `Py_GetArgcArgv()` function.

    Padrão: lista vazia.

    Novo na versão 3.10.

  int `parse_argv`

    Parse command line arguments?

    If equals to `1`, parse `argv` the same way the regular Python parses command line arguments, and strip Python arguments from `argv`.

    The `PyConfig_Read()` function only parses `PyConfig.argv` arguments once: `PyConfig.parse_argv` is set to `2` after arguments are parsed. Since Python arguments are strippped from `PyConfig.argv`, parsing arguments twice would parse the application options as Python options.

    Default: `1` in Python mode, `0` in isolated mode.

    Alterado na versão 3.10: The `PyConfig.argv` arguments are now only parsed if `PyConfig.parse_argv` equals to `1`.

  int `parser_debug`

    Parser debug mode. If greater than 0, turn on parser debugging output (for expert only, depending on compilation options).

    Incremented by the `-d` command line option. Set to the `PYTHONDEBUG` environment variable value.

    Padrão: `0`.

  int `pathconfig_warnings`

    On Unix, if non-zero, calculating the Python Path Configuration can log warnings into `stderr`. If equals to 0, suppress these warnings.

    It has no effect on Windows.

    Default: `1` in Python mode, `0` in isolated mode.

    Part of the Python Path Configuration input.

  wchar_t *`prefix`

    The site-specific directory prefix where the platform independent Python files are installed: `sys.prefix`.

    Padrão: `NULL`.

    Part of the Python Path Configuration output.

  wchar_t *`program_name`

    Program name used to initialize `executable` and in early error messages during Python initialization.

    - If `Py_SetProgramName()` has been called, use its argument.

    - On macOS, use `PYTHONEXECUTABLE` environment variable if set.

    - If the `WITH_NEXT_FRAMEWORK` macro is defined, use `__PYVENV_LAUNCHER__` environment variable if set.

    - Use `argv[0]` of `argv` if available and non-empty.

    - Otherwise, use `L"python"` on Windows, or `L"python3"` on other platforms.

    Padrão: `NULL`.

    Part of the Python Path Configuration input.

  wchar_t *`pycache_prefix`

    Directory where cached `.pyc` files are written: `sys.pycache_prefix`.

    Set by the `-X pycache_prefix=PATH` command line option and the `PYTHONPYCACHEPREFIX` environment variable.

    If `NULL`, `sys.pycache_prefix` is set to `None`.

    Padrão: `NULL`.

  int `quiet`

    Quiet mode. If greater than 0, don’t display the copyright and version at Python startup in interactive mode.

    Incremented by the `-q` command line option.

    Padrão: `0`.

  wchar_t *`run_command`

    Value of the `-c` command line option.

    Used by `Py_RunMain()`.

    Padrão: `NULL`.

  wchar_t *`run_filename`

    Filename passed on the command line: trailing command line argument without `-c` or `-m`.

    For example, it is set to `script.py` by the `python3 script.py arg` command.

    Used by `Py_RunMain()`.

    Padrão: `NULL`.

  wchar_t *`run_module`

    Value of the `-m` command line option.

    Used by `Py_RunMain()`.

    Padrão: `NULL`.

  int `show_ref_count`

    Show total reference count at exit?

    Set to 1 by `-X showrefcount` command line option.

    Need a debug build of Python (the `Py_REF_DEBUG` macro must be defined).

    Padrão: `0`.

  int `site_import`

    Import the `site` module at startup?

    If equal to zero, disable the import of the module site and the site-dependent manipulations of `sys.path` that it entails.

    Also disable these manipulations if the `site` module is explicitly imported later (call `site.main()` if you want them to be triggered).

    Set to `0` by the `-S` command line option.

    `sys.flags.no_site` is set to the inverted value of `site_import`.

    Padrão: `1`.

  int `skip_source_first_line`

    If non-zero, skip the first line of the `PyConfig.run_filename` source.

    It allows the usage of non-Unix forms of `#!cmd`. This is intended for a DOS specific hack only.

    Set to `1` by the `-x` command line option.

    Padrão: `0`.

  wchar_t *`stdio_encoding`
  wchar_t *`stdio_errors`

    Encoding and encoding errors of `sys.stdin`, `sys.stdout` and `sys.stderr` (but `sys.stderr` always uses `"backslashreplace"` error handler).

    If `Py_SetStandardStreamEncoding()` has been called, use its error and errors arguments if they are not `NULL`.

    Use the `PYTHONIOENCODING` environment variable if it is non-empty.

    Codificação padrão:

    - `"UTF-8"` if `PyPreConfig.utf8_mode` is non-zero.

    - Otherwise, use the locale encoding.

    Tratador de erros padrão:

    - On Windows: use `"surrogateescape"`.

    - `"surrogateescape"` if `PyPreConfig.utf8_mode` is non-zero, or if the LC_CTYPE locale is “C” or “POSIX”.

    - `"strict"` otherwise.

  int `tracemalloc`

    Enable tracemalloc?

    If non-zero, call `tracemalloc.start()` at startup.

    Set by `-X tracemalloc=N` command line option and by the `PYTHONTRACEMALLOC` environment variable.

    Padrão: `-1` no modo do Python, `0` no modo isolado.

  int `use_environment`

    Use environment variables?

    If equals to zero, ignore the environment variables.

    Padrão: `1` na configuração do Python e `0` na configuração isolada.

  int `user_site_directory`

    If non-zero, add the user site directory to `sys.path`.

    Set to `0` by the `-s` and `-I` command line options.

    Set to `0` by the `PYTHONNOUSERSITE` environment variable.

    Default: `1` in Python mode, `0` in isolated mode.

  int `verbose`

    Verbose mode. If greater than 0, print a message each time a module is imported, showing the place (filename or built-in module) from which it is loaded.

    If greater or equal to 2, print a message for each file that is checked for when searching for a module. Also provides information on module cleanup at exit.

    Incremented by the `-v` command line option.

    Set to the `PYTHONVERBOSE` environment variable value.

    Padrão: `0`.

  PyWideStringList `warnoptions`

    Options of the `warnings` module to build warnings filters, lowest to highest priority: `sys.warnoptions`.

    The `warnings` module adds `sys.warnoptions` in the reverse order: the last `PyConfig.warnoptions` item becomes the first item of `warnings.filters` which is checked first (highest priority).

    The `-W` command line options adds its value to `warnoptions`, it can be used multiple times.

    The `PYTHONWARNINGS` environment variable can also be used to add warning options. Multiple options can be specified, separated by commas (`,`).

    Padrão: lista vazia.

  int `write_bytecode`

    If equal to 0, Python won’t try to write `.pyc` files on the import of source modules.

    Set to `0` by the `-B` command line option and the `PYTHONDONTWRITEBYTECODE` environment variable.

    `sys.dont_write_bytecode` is initialized to the inverted value of `write_bytecode`.

    Padrão: `1`.

  PyWideStringList `xoptions`

    Values of the `-X` command line options: `sys._xoptions`.

    Padrão: lista vazia.

If `parse_argv` is non-zero, `argv` arguments are parsed the same way the regular Python parses command line arguments, and Python arguments are stripped from `argv`.

The `xoptions` options are parsed to set other options: see the `-X` command line option.

Alterado na versão 3.9: The `show_alloc_count` field has been removed.

## Initialization with PyConfig

Function to initialize Python:

PyStatus `Py_InitializeFromConfig`(const PyConfig *config)

  Initialize Python from config configuration.

O chamador é responsável por manipular exceções (erro ou saída) usando `PyStatus_Exception()` e `Py_ExitStatusException()`.

If `PyImport_FrozenModules()`, `PyImport_AppendInittab()` or `PyImport_ExtendInittab()` are used, they must be set or called after Python preinitialization and before the Python initialization. If Python is initialized multiple times, `PyImport_AppendInittab()` or `PyImport_ExtendInittab()` must be called before each Python initialization.

The current configuration (`PyConfig` type) is stored in `PyInterpreterState.config`.

Example setting the program name:

    void init_python(void)
    {
        PyStatus status;

        PyConfig config;
        PyConfig_InitPythonConfig(&config);

        /* Set the program name. Implicitly preinitialize Python. */
        status = PyConfig_SetString(&config, &config.program_name,
                                    L"/path/to/my_program");
        if (PyStatus_Exception(status)) {
            goto exception;
        }

        status = Py_InitializeFromConfig(&config);
        if (PyStatus_Exception(status)) {
            goto exception;
        }
        PyConfig_Clear(&config);
        return;

    exception:
        PyConfig_Clear(&config);
        Py_ExitStatusException(status);
    }

More complete example modifying the default configuration, read the configuration, and then override some parameters:

    PyStatus init_python(const char *program_name)
    {
        PyStatus status;

        PyConfig config;
        PyConfig_InitPythonConfig(&config);

        /* Set the program name before reading the configuration
           (decode byte string from the locale encoding).

           Implicitly preinitialize Python. */
        status = PyConfig_SetBytesString(&config, &config.program_name,
                                         program_name);
        if (PyStatus_Exception(status)) {
            goto done;
        }

        /* Read all configuration at once */
        status = PyConfig_Read(&config);
        if (PyStatus_Exception(status)) {
            goto done;
        }

        /* Append our custom search path to sys.path */
        status = PyWideStringList_Append(&config.module_search_paths,
                                         L"/path/to/more/modules");
        if (PyStatus_Exception(status)) {
            goto done;
        }

        /* Override executable computed by PyConfig_Read() */
        status = PyConfig_SetString(&config, &config.executable,
                                    L"/path/to/my_executable");
        if (PyStatus_Exception(status)) {
            goto done;
        }

        status = Py_InitializeFromConfig(&config);

    done:
        PyConfig_Clear(&config);
        return status;
    }

## Isolated Configuration

`PyPreConfig_InitIsolatedConfig()` and `PyConfig_InitIsolatedConfig()` functions create a configuration to isolate Python from the system. For example, to embed Python into an application.

This configuration ignores global configuration variables, environment variables, command line arguments (`PyConfig.argv` is not parsed) and user site directory. The C standard streams (ex: `stdout`) and the LC_CTYPE locale are left unchanged. Signal handlers are not installed.

Configuration files are still used with this configuration. Set the Python Path Configuration (“output fields”) to ignore these configuration files and avoid the function computing the default path configuration.

## Configuração do Python

`PyPreConfig_InitPythonConfig()` and `PyConfig_InitPythonConfig()` functions create a configuration to build a customized Python which behaves as the regular Python.

Environments variables and command line arguments are used to configure Python, whereas global configuration variables are ignored.

This function enables C locale coercion (PEP 538) and Python UTF-8 Mode (PEP 540) depending on the LC_CTYPE locale, `PYTHONUTF8` and `PYTHONCOERCECLOCALE` environment variables.

## Python Path Configuration

`PyConfig` contains multiple fields for the path configuration:

- Path configuration inputs:

  - `PyConfig.home`

  - `PyConfig.platlibdir`

  - `PyConfig.pathconfig_warnings`

  - `PyConfig.program_name`

  - `PyConfig.pythonpath_env`

  - current working directory: to get absolute paths

  - `PATH` environment variable to get the program full path (from `PyConfig.program_name`)

  - `__PYVENV_LAUNCHER__` environment variable

  - (Windows only) Application paths in the registry under “SoftwarePythonPythonCoreX.YPythonPath” of HKEY_CURRENT_USER and HKEY_LOCAL_MACHINE (where X.Y is the Python version).

- Path configuration output fields:

  - `PyConfig.base_exec_prefix`

  - `PyConfig.base_executable`

  - `PyConfig.base_prefix`

  - `PyConfig.exec_prefix`

  - `PyConfig.executable`

  - `PyConfig.module_search_paths_set`, `PyConfig.module_search_paths`

  - `PyConfig.prefix`

If at least one “output field” is not set, Python calculates the path configuration to fill unset fields. If `module_search_paths_set` is equal to 0, `module_search_paths` is overridden and `module_search_paths_set` is set to 1.

It is possible to completely ignore the function calculating the default path configuration by setting explicitly all path configuration output fields listed above. A string is considered as set even if it is non-empty. `module_search_paths` is considered as set if `module_search_paths_set` is set to 1. In this case, path configuration input fields are ignored as well.

Set `pathconfig_warnings` to 0 to suppress warnings when calculating the path configuration (Unix only, Windows does not log any warning).

If `base_prefix` or `base_exec_prefix` fields are not set, they inherit their value from `prefix` and `exec_prefix` respectively.

`Py_RunMain()` and `Py_Main()` modify `sys.path`:

- If `run_filename` is set and is a directory which contains a `__main__.py` script, prepend `run_filename` to `sys.path`.

- If `isolated` is zero:

  - If `run_module` is set, prepend the current directory to `sys.path`. Do nothing if the current directory cannot be read.

  - If `run_filename` is set, prepend the directory of the filename to `sys.path`.

  - Otherwise, prepend an empty string to `sys.path`.

If `site_import` is non-zero, `sys.path` can be modified by the `site` module. If `user_site_directory` is non-zero and the user’s site-package directory exists, the `site` module appends the user’s site-package directory to `sys.path`.

The following configuration files are used by the path configuration:

- `pyvenv.cfg`

- `python._pth` (Windows only)

- `pybuilddir.txt` (Unix only)

The `__PYVENV_LAUNCHER__` environment variable is used to set `PyConfig.base_executable`

## Py_RunMain()

int `Py_RunMain`(void)

  Execute the command (`PyConfig.run_command`), the script (`PyConfig.run_filename`) or the module (`PyConfig.run_module`) specified on the command line or in the configuration.

  By default and when if `-i` option is used, run the REPL.

  Finally, finalizes Python and returns an exit status that can be passed to the `exit()` function.

See Python Configuration for an example of customized Python always running in isolated mode using `Py_RunMain()`.

## Py_GetArgcArgv()

void `Py_GetArgcArgv`(int *argc, wchar_t ***argv)

  Get the original command line arguments, before Python modified them.

  See also `PyConfig.orig_argv` member.

## Multi-Phase Initialization Private Provisional API

This section is a private provisional API introducing multi-phase initialization, the core feature of PEP 432:

- “Core” initialization phase, “bare minimum Python”:

  - Builtin types;

  - Builtin exceptions;

  - Builtin and frozen modules;

  - The `sys` module is only partially initialized (ex: `sys.path` doesn’t exist yet).

- “Main” initialization phase, Python is fully initialized:

  - Install and configure `importlib`;

  - Apply the Path Configuration;

  - Install signal handlers;

  - Finish `sys` module initialization (ex: create `sys.stdout` and `sys.path`);

  - Enable optional features like `faulthandler` and `tracemalloc`;

  - Import the `site` module;

  - etc.

Private provisional API:

- `PyConfig._init_main`: if set to 0, `Py_InitializeFromConfig()` stops at the “Core” initialization phase.

- `PyConfig._isolated_interpreter`: if non-zero, disallow threads, subprocesses and fork.

PyStatus `_Py_InitializeMain`(void)

  Move to the “Main” initialization phase, finish the Python initialization.

No module is imported during the “Core” phase and the `importlib` module is not configured: the Path Configuration is only applied during the “Main” phase. It may allow to customize Python in Python to override or tune the Path Configuration, maybe install a custom `sys.meta_path` importer or an import hook, etc.

It may become possible to calculatin the Path Configuration in Python, after the Core phase and before the Main phase, which is one of the PEP 432 motivation.

The “Core” phase is not properly defined: what should be and what should not be available at this phase is not specified yet. The API is marked as private and provisional: the API can be modified or even be removed anytime until a proper public API is designed.

Example running Python code between “Core” and “Main” initialization phases:

    void init_python(void)
    {
        PyStatus status;

        PyConfig config;
        PyConfig_InitPythonConfig(&config);
        config._init_main = 0;

        /* ... customize 'config' configuration ... */

        status = Py_InitializeFromConfig(&config);
        PyConfig_Clear(&config);
        if (PyStatus_Exception(status)) {
            Py_ExitStatusException(status);
        }

        /* Use sys.stderr because sys.stdout is only created
           by _Py_InitializeMain() */
        int res = PyRun_SimpleString(
            "import sys; "
            "print('Run Python code before _Py_InitializeMain', "
                   "file=sys.stderr)");
        if (res < 0) {
            exit(1);
        }

        /* ... put more configuration code here ... */

        status = _Py_InitializeMain();
        if (PyStatus_Exception(status)) {
            Py_ExitStatusException(status);
        }
    }