Configuração de Inicialização do Python¶

PyConfig C API¶

Adicionado 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_MIMALLOC (6): usa mimalloc, um substituto rápido do malloc.
PYMEM_ALLOCATOR_MIMALLOC_DEBUG (7): use mimalloc, um substituto rápido do malloc com ganchos de depuração.

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

PYMEM_ALLOCATOR_MIMALLOC e PYMEM_ALLOCATOR_MIMALLOC_DEBUG não são suportados se o Python estiver configurado usando --without-mimalloc ou se suporte atômico subjacente não estiver disponível.

Veja Gerenciamento de memória.

Padrão: PYMEM_ALLOCATOR_NOT_SET.

int configure_locale¶

Define a localidade LC_CTYPE para a localidade preferida do usuário.

Se igual a 0, define os membros coerce_c_locale e coerce_c_locale_warn para 0.

Veja a codificação da localidade.

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

int coerce_c_locale¶

Se igual a 2, força a localidade para C.

Se for igual a 1, lê a localidade LC_CTYPE para decidir se deve ser forçado.

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¶

Modo de desenvolvimento do Python: veja 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".

Initialized from the PYTHONLEGACYWINDOWSFSENCODING environment variable value.

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.

Define para 0 ou 1 pela opção de linha de comando -X utf8 e a variável de ambiente PYTHONUTF8.

Também define como 1 se a localidade LC_CTYPE for C ou POSIX.

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.

Fields for path configuration are no longer calculated or modified when calling this function, as of Python 3.11.

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 stripped 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.

Alterado na versão 3.11: PyConfig_Read() no longer calculates all paths, and so fields listed under Python Path Configuration may no longer be updated until Py_InitializeFromConfig() is called.

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¶

Set sys.argv command line arguments based on argv. These parameters are similar to those passed to the program’s main() function with the difference that the first entry should refer to the script file to be executed rather than the executable hosting the Python interpreter. If there isn’t a script that will be run, the first entry in argv can be an empty string.

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.

Initialization with PyConfig¶

Initializing the interpreter from a populated configuration struct is handled by calling Py_InitializeFromConfig().

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. Note that since 3.11, many parameters are not calculated until initialization, and so values cannot be read from the configuration structure. Any values set before initialize is called will be left unchanged by initialization:

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;
    }

    /* Specify sys.path explicitly */
    /* If you want to modify the default set of paths, finish
       initialization first and then use PySys_GetObject("path") */
    config.module_search_paths_set = 1;
    status = PyWideStringList_Append(&config.module_search_paths,
                                     L"/path/to/stdlib");
    if (PyStatus_Exception(status)) {
        goto done;
    }
    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 to determine paths that are unspecified. Ensure PyConfig.home is specified to avoid 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:

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, module_search_paths will be used without modification.

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
._pth file (ex: python._pth)
pybuilddir.txt (Unix only)

If a ._pth file is present:

Set isolated to 1.
Set use_environment to 0.
Set site_import to 0.
Set safe_path to 1.

If home is not set and a pyvenv.cfg file is present in the same directory as executable, or its parent, prefix and exec_prefix are set that location. When this happens, base_prefix and base_exec_prefix still keep their value, pointing to the base installation. See Virtual Environments for more information.

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

Alterado na versão 3.14: prefix, and exec_prefix, are now set to the pyvenv.cfg directory. This was previously done by site, therefore affected by -S.

PyInitConfig C API¶

C API to configure the Python initialization (PEP 741).

Adicionado na versão 3.14.

Create Config¶

struct PyInitConfig¶: Opaque structure to configure the Python initialization.

PyInitConfig *PyInitConfig_Create(void)¶

Create a new initialization configuration using Isolated Configuration default values.

It must be freed by PyInitConfig_Free().

Return NULL on memory allocation failure.

void PyInitConfig_Free(PyInitConfig *config)¶

Free memory of the initialization configuration config.

If config is NULL, no operation is performed.

Error Handling¶

int PyInitConfig_GetError(PyInitConfig *config, const char **err_msg)¶

Get the config error message.

Set *err_msg and return 1 if an error is set.
Set *err_msg to NULL and return 0 otherwise.

An error message is an UTF-8 encoded string.

If config has an exit code, format the exit code as an error message.

The error message remains valid until another PyInitConfig function is called with config. The caller doesn’t have to free the error message.

int PyInitConfig_GetExitCode(PyInitConfig *config, int *exitcode)¶

Get the config exit code.

Set *exitcode and return 1 if config has an exit code set.
Return 0 if config has no exit code set.

Only the Py_InitializeFromInitConfig() function can set an exit code if the parse_argv option is non-zero.

An exit code can be set when parsing the command line failed (exit code 2) or when a command line option asks to display the command line help (exit code 0).

Get Options¶

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string.

int PyInitConfig_HasOption(PyInitConfig *config, const char *name)¶

Test if the configuration has an option called name.

Return 1 if the option exists, or return 0 otherwise.

int PyInitConfig_GetInt(PyInitConfig *config, const char *name, int64_t *value)¶

Get an integer configuration option.

Set *value, and return 0 on success.
Set an error in config and return -1 on error.

int PyInitConfig_GetStr(PyInitConfig *config, const char *name, char **value)¶

Get a string configuration option as a null-terminated UTF-8 encoded string.

Set *value, and return 0 on success.
Set an error in config and return -1 on error.

*value can be set to NULL if the option is an optional string and the option is unset.

On success, the string must be released with free(value) if it’s not NULL.

int PyInitConfig_GetStrList(PyInitConfig *config, const char *name, size_t *length, char ***items)¶

Get a string list configuration option as an array of null-terminated UTF-8 encoded strings.

Set *length and *value, and return 0 on success.
Set an error in config and return -1 on error.

On success, the string list must be released with PyInitConfig_FreeStrList(length, items).

void PyInitConfig_FreeStrList(size_t length, char **items)¶: Free memory of a string list created by PyInitConfig_GetStrList().

Set Options¶

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string.

Some configuration options have side effects on other options. This logic is only implemented when Py_InitializeFromInitConfig() is called, not by the “Set” functions below. For example, setting dev_mode to 1 does not set faulthandler to 1.

int PyInitConfig_SetInt(PyInitConfig *config, const char *name, int64_t value)¶

Set an integer configuration option.

Return 0 on success.
Set an error in config and return -1 on error.

int PyInitConfig_SetStr(PyInitConfig *config, const char *name, const char *value)¶

Set a string configuration option from a null-terminated UTF-8 encoded string. The string is copied.

Return 0 on success.
Set an error in config and return -1 on error.

int PyInitConfig_SetStrList(PyInitConfig *config, const char *name, size_t length, char *const *items)¶

Set a string list configuration option from an array of null-terminated UTF-8 encoded strings. The string list is copied.

Return 0 on success.
Set an error in config and return -1 on error.

Module¶

int PyInitConfig_AddModule(PyInitConfig *config, const char *name, PyObject *(*initfunc)(void))¶

Add a built-in extension module to the table of built-in modules.

The new module can be imported by the name name, and uses the function initfunc as the initialization function called on the first attempted import.

Return 0 on success.
Set an error in config and return -1 on error.

If Python is initialized multiple times, PyInitConfig_AddModule() must be called at each Python initialization.

Similar to the PyImport_AppendInittab() function.

Initialize Python¶

int Py_InitializeFromInitConfig(PyInitConfig *config)¶

Initialize Python from the initialization configuration.

Return 0 on success.
Set an error in config and return -1 on error.
Set an exit code in config and return -1 if Python wants to exit.

See PyInitConfig_GetExitcode() for the exit code case.

Exemplo¶

Example initializing Python, set configuration options of various types, return -1 on error:

int init_python(void)
{
    PyInitConfig *config = PyInitConfig_Create();
    if (config == NULL) {
        printf("PYTHON INIT ERROR: memory allocation failed\n");
        return -1;
    }

    // Set an integer (dev mode)
    if (PyInitConfig_SetInt(config, "dev_mode", 1) < 0) {
        goto error;
    }

    // Set a list of UTF-8 strings (argv)
    char *argv[] = {"my_program", "-c", "pass"};
    if (PyInitConfig_SetStrList(config, "argv",
                                 Py_ARRAY_LENGTH(argv), argv) < 0) {
        goto error;
    }

    // Set a UTF-8 string (program name)
    if (PyInitConfig_SetStr(config, "program_name", L"my_program") < 0) {
        goto error;
    }

    // Initialize Python with the configuration
    if (Py_InitializeFromInitConfig(config) < 0) {
        goto error;
    }
    PyInitConfig_Free(config);
    return 0;

error:
    {
        // Display the error message
        // This uncommon braces style is used, because you cannot make
        // goto targets point to variable declarations.
        const char *err_msg;
        (void)PyInitConfig_GetError(config, &err_msg);
        printf("PYTHON INIT ERROR: %s\n", err_msg);
        PyInitConfig_Free(config);

        return -1;
    }
}

Runtime Python configuration API¶

The configuration option name parameter must be a non-NULL null-terminated UTF-8 encoded string.

Some options are read from the sys attributes. For example, the option "argv" is read from sys.argv.

PyObject *PyConfig_Get(const char *name)¶

Get the current runtime value of a configuration option as a Python object.

Return a new reference on success.
Set an exception and return NULL on error.

The object type depends on the configuration option. It can be:

bool
int
str
list[str]
dict[str, str]

The caller must hold the GIL. The function cannot be called before Python initialization nor after Python finalization.

Adicionado na versão 3.14.

int PyConfig_GetInt(const char *name, int *value)¶

Similar to PyConfig_Get(), but get the value as a C int.

Return 0 on success.
Set an exception and return -1 on error.

Adicionado na versão 3.14.

PyObject *PyConfig_Names(void)¶

Get all configuration option names as a frozenset.

Return a new reference on success.
Set an exception and return NULL on error.

The caller must hold the GIL. The function cannot be called before Python initialization nor after Python finalization.

Adicionado na versão 3.14.

int PyConfig_Set(const char *name, PyObject *value)¶

Set the current runtime value of a configuration option.

Raise a ValueError if there is no option name.
Raise a ValueError if value is an invalid value.
Raise a ValueError if the option is read-only (cannot be set).
Raise a TypeError if value has not the proper type.

The caller must hold the GIL. The function cannot be called before Python initialization nor after Python finalization.

Adicionado na versão 3.14.

Py_GetArgcArgv()¶

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

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

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.

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 calculate 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);
    }
}

Configuração de Inicialização do Python¶

PyConfig C API¶

Exemplo¶

PyWideStringList¶

PyStatus¶

PyPreConfig¶

Pré-inicializar Python com PyPreConfig¶

PyConfig¶

Initialization with PyConfig¶

Isolated Configuration¶

Configuração do Python¶

Python Path Configuration¶

PyInitConfig C API¶

Create Config¶

Error Handling¶

Get Options¶

Set Options¶

Module¶

Initialize Python¶

Exemplo¶

Runtime Python configuration API¶

Py_GetArgcArgv()¶

Multi-Phase Initialization Private Provisional API¶

Tabela de Conteúdo

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