_Py_InitializeMainInterpreter Definition

pylifecycle.c

/* Update interpreter state based on supplied configuration settings
 *
 * After calling this function, most of the restrictions on the interpreter
 * are lifted. The only remaining incomplete settings are those related
 * to the main module (sys.argv[0], __main__ metadata)
 *
 * Calling this when the interpreter is not initializing, is already
 * initialized or without a valid current thread state is a fatal error.
 * Other errors should be reported as normal Python exceptions with a
 * non-zero return code.
 */
int _Py_InitializeMainInterpreter(const _PyMainInterpreterConfig *config)
{
    PyInterpreterState *interp;
    PyThreadState *tstate;

    if (!_Py_CoreInitialized) {
        Py_FatalError("Py_InitializeMainInterpreter: runtime core not initialized");
    }
    if (_Py_Initialized) {
        Py_FatalError("Py_InitializeMainInterpreter: main interpreter already initialized");
    }

    /* Get current thread state and interpreter pointer */
    tstate = PyThreadState_GET();
    if (!tstate)
        Py_FatalError("Py_InitializeMainInterpreter: failed to read thread state");
    interp = tstate->interp;
    if (!interp)
        Py_FatalError("Py_InitializeMainInterpreter: failed to get interpreter");

    /* Now finish configuring the main interpreter */
    interp->config = *config;

    if (interp->core_config._disable_importlib) {
        /* Special mode for freeze_importlib: run with no import system
         *
         * This means anything which needs support from extension modules
         * or pure Python code in the standard library won't work.
         */
        _Py_Initialized = 1;
        return 0;
    }
    /* TODO: Report exceptions rather than fatal errors below here */

    if (_PyTime_Init() < 0)
        Py_FatalError("Py_InitializeMainInterpreter: can't initialize time");

    /* Finish setting up the sys module and import system */
    /* GetPath may initialize state that _PySys_EndInit locks
       in, and so has to be called first. */
    /* TODO: Call Py_GetPath() in Py_ReadConfig, rather than here */
    PySys_SetPath(Py_GetPath());
    if (_PySys_EndInit(interp->sysdict) < 0)
        Py_FatalError("Py_InitializeMainInterpreter: can't finish initializing sys");
    initexternalimport(interp);

    /* initialize the faulthandler module */
    if (_PyFaulthandler_Init())
        Py_FatalError("Py_InitializeMainInterpreter: can't initialize faulthandler");

    if (initfsencoding(interp) < 0)
        Py_FatalError("Py_InitializeMainInterpreter: unable to load the file system codec");

    if (config->install_signal_handlers)
        initsigs(); /* Signal handling stuff, including initintr() */

    if (_PyTraceMalloc_Init() < 0)
        Py_FatalError("Py_InitializeMainInterpreter: can't initialize tracemalloc");

    initmain(interp); /* Module __main__ */
    if (initstdio() < 0)
        Py_FatalError(
            "Py_InitializeMainInterpreter: can't initialize sys standard streams");

    /* Initialize warnings. */
    if (PySys_HasWarnOptions()) {
        PyObject *warnings_module = PyImport_ImportModule("warnings");
        if (warnings_module == NULL) {
            fprintf(stderr, "'import warnings' failed; traceback:\n");
            PyErr_Print();
        }
        Py_XDECREF(warnings_module);
    }

    _Py_Initialized = 1;

    if (!Py_NoSiteFlag)
        initsite(); /* Module site */

    return 0;
}