vidya7732/AI_Doctor_LLM_GenModel

1#ifndef Py_OBJECT_H2#define Py_OBJECT_H3 4#ifdef __cplusplus5extern "C" {6#endif7 8 9/* Object and type object interface */10 11/*12Objects are structures allocated on the heap.  Special rules apply to13the use of objects to ensure they are properly garbage-collected.14Objects are never allocated statically or on the stack; they must be15accessed through special macros and functions only.  (Type objects are16exceptions to the first rule; the standard types are represented by17statically initialized type objects, although work on type/class unification18for Python 2.2 made it possible to have heap-allocated type objects too).19 20An object has a 'reference count' that is increased or decreased when a21pointer to the object is copied or deleted; when the reference count22reaches zero there are no references to the object left and it can be23removed from the heap.24 25An object has a 'type' that determines what it represents and what kind26of data it contains.  An object's type is fixed when it is created.27Types themselves are represented as objects; an object contains a28pointer to the corresponding type object.  The type itself has a type29pointer pointing to the object representing the type 'type', which30contains a pointer to itself!.31 32Objects do not float around in memory; once allocated an object keeps33the same size and address.  Objects that must hold variable-size data34can contain pointers to variable-size parts of the object.  Not all35objects of the same type have the same size; but the size cannot change36after allocation.  (These restrictions are made so a reference to an37object can be simply a pointer -- moving an object would require38updating all the pointers, and changing an object's size would require39moving it if there was another object right next to it.)40 41Objects are always accessed through pointers of the type 'PyObject *'.42The type 'PyObject' is a structure that only contains the reference count43and the type pointer.  The actual memory allocated for an object44contains other data that can only be accessed after casting the pointer45to a pointer to a longer structure type.  This longer type must start46with the reference count and type fields; the macro PyObject_HEAD should be47used for this (to accommodate for future changes).  The implementation48of a particular object type can cast the object pointer to the proper49type and back.50 51A standard interface exists for objects that contain an array of items52whose size is determined when the object is allocated.53*/54 55/* Py_DEBUG implies Py_REF_DEBUG. */56#if defined(Py_DEBUG) && !defined(Py_REF_DEBUG)57#define Py_REF_DEBUG58#endif59 60#if defined(Py_LIMITED_API) && defined(Py_REF_DEBUG)61#error Py_LIMITED_API is incompatible with Py_DEBUG, Py_TRACE_REFS, and Py_REF_DEBUG62#endif63 64/* PyTypeObject structure is defined in cpython/object.h.65   In Py_LIMITED_API, PyTypeObject is an opaque structure. */66typedef struct _typeobject PyTypeObject;67 68#ifdef Py_TRACE_REFS69/* Define pointers to support a doubly-linked list of all live heap objects. */70#define _PyObject_HEAD_EXTRA            \71    struct _object *_ob_next;           \72    struct _object *_ob_prev;73 74#define _PyObject_EXTRA_INIT 0, 0,75 76#else77#define _PyObject_HEAD_EXTRA78#define _PyObject_EXTRA_INIT79#endif80 81/* PyObject_HEAD defines the initial segment of every PyObject. */82#define PyObject_HEAD                   PyObject ob_base;83 84#define PyObject_HEAD_INIT(type)        \85    { _PyObject_EXTRA_INIT              \86    1, type },87 88#define PyVarObject_HEAD_INIT(type, size)       \89    { PyObject_HEAD_INIT(type) size },90 91/* PyObject_VAR_HEAD defines the initial segment of all variable-size92 * container objects.  These end with a declaration of an array with 193 * element, but enough space is malloc'ed so that the array actually94 * has room for ob_size elements.  Note that ob_size is an element count,95 * not necessarily a byte count.96 */97#define PyObject_VAR_HEAD      PyVarObject ob_base;98#define Py_INVALID_SIZE (Py_ssize_t)-199 100/* Nothing is actually declared to be a PyObject, but every pointer to101 * a Python object can be cast to a PyObject*.  This is inheritance built102 * by hand.  Similarly every pointer to a variable-size Python object can,103 * in addition, be cast to PyVarObject*.104 */105typedef struct _object {106    _PyObject_HEAD_EXTRA107    Py_ssize_t ob_refcnt;108    PyTypeObject *ob_type;109} PyObject;110 111/* Cast argument to PyObject* type. */112#define _PyObject_CAST(op) ((PyObject*)(op))113#define _PyObject_CAST_CONST(op) ((const PyObject*)(op))114 115typedef struct {116    PyObject ob_base;117    Py_ssize_t ob_size; /* Number of items in variable part */118} PyVarObject;119 120/* Cast argument to PyVarObject* type. */121#define _PyVarObject_CAST(op) ((PyVarObject*)(op))122 123#define Py_REFCNT(ob)           (_PyObject_CAST(ob)->ob_refcnt)124#define Py_TYPE(ob)             (_PyObject_CAST(ob)->ob_type)125#define Py_SIZE(ob)             (_PyVarObject_CAST(ob)->ob_size)126 127static inline int _Py_IS_TYPE(const PyObject *ob, const PyTypeObject *type) {128    return ob->ob_type == type;129}130#define Py_IS_TYPE(ob, type) _Py_IS_TYPE(_PyObject_CAST_CONST(ob), type)131 132static inline void _Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) {133    ob->ob_refcnt = refcnt;134}135#define Py_SET_REFCNT(ob, refcnt) _Py_SET_REFCNT(_PyObject_CAST(ob), refcnt)136 137static inline void _Py_SET_TYPE(PyObject *ob, PyTypeObject *type) {138    ob->ob_type = type;139}140#define Py_SET_TYPE(ob, type) _Py_SET_TYPE(_PyObject_CAST(ob), type)141 142static inline void _Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size) {143    ob->ob_size = size;144}145#define Py_SET_SIZE(ob, size) _Py_SET_SIZE(_PyVarObject_CAST(ob), size)146 147 148/*149Type objects contain a string containing the type name (to help somewhat150in debugging), the allocation parameters (see PyObject_New() and151PyObject_NewVar()),152and methods for accessing objects of the type.  Methods are optional, a153nil pointer meaning that particular kind of access is not available for154this type.  The Py_DECREF() macro uses the tp_dealloc method without155checking for a nil pointer; it should always be implemented except if156the implementation can guarantee that the reference count will never157reach zero (e.g., for statically allocated type objects).158 159NB: the methods for certain type groups are now contained in separate160method blocks.161*/162 163typedef PyObject * (*unaryfunc)(PyObject *);164typedef PyObject * (*binaryfunc)(PyObject *, PyObject *);165typedef PyObject * (*ternaryfunc)(PyObject *, PyObject *, PyObject *);166typedef int (*inquiry)(PyObject *);167typedef Py_ssize_t (*lenfunc)(PyObject *);168typedef PyObject *(*ssizeargfunc)(PyObject *, Py_ssize_t);169typedef PyObject *(*ssizessizeargfunc)(PyObject *, Py_ssize_t, Py_ssize_t);170typedef int(*ssizeobjargproc)(PyObject *, Py_ssize_t, PyObject *);171typedef int(*ssizessizeobjargproc)(PyObject *, Py_ssize_t, Py_ssize_t, PyObject *);172typedef int(*objobjargproc)(PyObject *, PyObject *, PyObject *);173 174typedef int (*objobjproc)(PyObject *, PyObject *);175typedef int (*visitproc)(PyObject *, void *);176typedef int (*traverseproc)(PyObject *, visitproc, void *);177 178 179typedef void (*freefunc)(void *);180typedef void (*destructor)(PyObject *);181typedef PyObject *(*getattrfunc)(PyObject *, char *);182typedef PyObject *(*getattrofunc)(PyObject *, PyObject *);183typedef int (*setattrfunc)(PyObject *, char *, PyObject *);184typedef int (*setattrofunc)(PyObject *, PyObject *, PyObject *);185typedef PyObject *(*reprfunc)(PyObject *);186typedef Py_hash_t (*hashfunc)(PyObject *);187typedef PyObject *(*richcmpfunc) (PyObject *, PyObject *, int);188typedef PyObject *(*getiterfunc) (PyObject *);189typedef PyObject *(*iternextfunc) (PyObject *);190typedef PyObject *(*descrgetfunc) (PyObject *, PyObject *, PyObject *);191typedef int (*descrsetfunc) (PyObject *, PyObject *, PyObject *);192typedef int (*initproc)(PyObject *, PyObject *, PyObject *);193typedef PyObject *(*newfunc)(PyTypeObject *, PyObject *, PyObject *);194typedef PyObject *(*allocfunc)(PyTypeObject *, Py_ssize_t);195 196typedef struct{197    int slot;    /* slot id, see below */198    void *pfunc; /* function pointer */199} PyType_Slot;200 201typedef struct{202    const char* name;203    int basicsize;204    int itemsize;205    unsigned int flags;206    PyType_Slot *slots; /* terminated by slot==0. */207} PyType_Spec;208 209PyAPI_FUNC(PyObject*) PyType_FromSpec(PyType_Spec*);210#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000211PyAPI_FUNC(PyObject*) PyType_FromSpecWithBases(PyType_Spec*, PyObject*);212#endif213#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03040000214PyAPI_FUNC(void*) PyType_GetSlot(PyTypeObject*, int);215#endif216#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03090000217PyAPI_FUNC(PyObject*) PyType_FromModuleAndSpec(PyObject *, PyType_Spec *, PyObject *);218PyAPI_FUNC(PyObject *) PyType_GetModule(struct _typeobject *);219PyAPI_FUNC(void *) PyType_GetModuleState(struct _typeobject *);220#endif221 222/* Generic type check */223PyAPI_FUNC(int) PyType_IsSubtype(PyTypeObject *, PyTypeObject *);224#define PyObject_TypeCheck(ob, tp) \225    (Py_IS_TYPE(ob, tp) || PyType_IsSubtype(Py_TYPE(ob), (tp)))226 227PyAPI_DATA(PyTypeObject) PyType_Type; /* built-in 'type' */228PyAPI_DATA(PyTypeObject) PyBaseObject_Type; /* built-in 'object' */229PyAPI_DATA(PyTypeObject) PySuper_Type; /* built-in 'super' */230 231PyAPI_FUNC(unsigned long) PyType_GetFlags(PyTypeObject*);232 233PyAPI_FUNC(int) PyType_Ready(PyTypeObject *);234PyAPI_FUNC(PyObject *) PyType_GenericAlloc(PyTypeObject *, Py_ssize_t);235PyAPI_FUNC(PyObject *) PyType_GenericNew(PyTypeObject *,236                                               PyObject *, PyObject *);237PyAPI_FUNC(unsigned int) PyType_ClearCache(void);238PyAPI_FUNC(void) PyType_Modified(PyTypeObject *);239 240/* Generic operations on objects */241PyAPI_FUNC(PyObject *) PyObject_Repr(PyObject *);242PyAPI_FUNC(PyObject *) PyObject_Str(PyObject *);243PyAPI_FUNC(PyObject *) PyObject_ASCII(PyObject *);244PyAPI_FUNC(PyObject *) PyObject_Bytes(PyObject *);245PyAPI_FUNC(PyObject *) PyObject_RichCompare(PyObject *, PyObject *, int);246PyAPI_FUNC(int) PyObject_RichCompareBool(PyObject *, PyObject *, int);247PyAPI_FUNC(PyObject *) PyObject_GetAttrString(PyObject *, const char *);248PyAPI_FUNC(int) PyObject_SetAttrString(PyObject *, const char *, PyObject *);249PyAPI_FUNC(int) PyObject_HasAttrString(PyObject *, const char *);250PyAPI_FUNC(PyObject *) PyObject_GetAttr(PyObject *, PyObject *);251PyAPI_FUNC(int) PyObject_SetAttr(PyObject *, PyObject *, PyObject *);252PyAPI_FUNC(int) PyObject_HasAttr(PyObject *, PyObject *);253PyAPI_FUNC(PyObject *) PyObject_SelfIter(PyObject *);254PyAPI_FUNC(PyObject *) PyObject_GenericGetAttr(PyObject *, PyObject *);255PyAPI_FUNC(int) PyObject_GenericSetAttr(PyObject *, PyObject *, PyObject *);256#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x03030000257PyAPI_FUNC(int) PyObject_GenericSetDict(PyObject *, PyObject *, void *);258#endif259PyAPI_FUNC(Py_hash_t) PyObject_Hash(PyObject *);260PyAPI_FUNC(Py_hash_t) PyObject_HashNotImplemented(PyObject *);261PyAPI_FUNC(int) PyObject_IsTrue(PyObject *);262PyAPI_FUNC(int) PyObject_Not(PyObject *);263PyAPI_FUNC(int) PyCallable_Check(PyObject *);264PyAPI_FUNC(void) PyObject_ClearWeakRefs(PyObject *);265 266/* PyObject_Dir(obj) acts like Python builtins.dir(obj), returning a267   list of strings.  PyObject_Dir(NULL) is like builtins.dir(),268   returning the names of the current locals.  In this case, if there are269   no current locals, NULL is returned, and PyErr_Occurred() is false.270*/271PyAPI_FUNC(PyObject *) PyObject_Dir(PyObject *);272 273 274/* Helpers for printing recursive container types */275PyAPI_FUNC(int) Py_ReprEnter(PyObject *);276PyAPI_FUNC(void) Py_ReprLeave(PyObject *);277 278/* Flag bits for printing: */279#define Py_PRINT_RAW    1       /* No string quotes etc. */280 281/*282Type flags (tp_flags)283 284These flags are used to change expected features and behavior for a285particular type.286 287Arbitration of the flag bit positions will need to be coordinated among288all extension writers who publicly release their extensions (this will289be fewer than you might expect!).290 291Most flags were removed as of Python 3.0 to make room for new flags.  (Some292flags are not for backwards compatibility but to indicate the presence of an293optional feature; these flags remain of course.)294 295Type definitions should use Py_TPFLAGS_DEFAULT for their tp_flags value.296 297Code can use PyType_HasFeature(type_ob, flag_value) to test whether the298given type object has a specified feature.299*/300 301/* Set if the type object is dynamically allocated */302#define Py_TPFLAGS_HEAPTYPE (1UL << 9)303 304/* Set if the type allows subclassing */305#define Py_TPFLAGS_BASETYPE (1UL << 10)306 307/* Set if the type implements the vectorcall protocol (PEP 590) */308#ifndef Py_LIMITED_API309#define Py_TPFLAGS_HAVE_VECTORCALL (1UL << 11)310// Backwards compatibility alias for API that was provisional in Python 3.8311#define _Py_TPFLAGS_HAVE_VECTORCALL Py_TPFLAGS_HAVE_VECTORCALL312#endif313 314/* Set if the type is 'ready' -- fully initialized */315#define Py_TPFLAGS_READY (1UL << 12)316 317/* Set while the type is being 'readied', to prevent recursive ready calls */318#define Py_TPFLAGS_READYING (1UL << 13)319 320/* Objects support garbage collection (see objimpl.h) */321#define Py_TPFLAGS_HAVE_GC (1UL << 14)322 323/* These two bits are preserved for Stackless Python, next after this is 17 */324#ifdef STACKLESS325#define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION (3UL << 15)326#else327#define Py_TPFLAGS_HAVE_STACKLESS_EXTENSION 0328#endif329 330/* Objects behave like an unbound method */331#define Py_TPFLAGS_METHOD_DESCRIPTOR (1UL << 17)332 333/* Objects support type attribute cache */334#define Py_TPFLAGS_HAVE_VERSION_TAG   (1UL << 18)335#define Py_TPFLAGS_VALID_VERSION_TAG  (1UL << 19)336 337/* Type is abstract and cannot be instantiated */338#define Py_TPFLAGS_IS_ABSTRACT (1UL << 20)339 340/* These flags are used to determine if a type is a subclass. */341#define Py_TPFLAGS_LONG_SUBCLASS        (1UL << 24)342#define Py_TPFLAGS_LIST_SUBCLASS        (1UL << 25)343#define Py_TPFLAGS_TUPLE_SUBCLASS       (1UL << 26)344#define Py_TPFLAGS_BYTES_SUBCLASS       (1UL << 27)345#define Py_TPFLAGS_UNICODE_SUBCLASS     (1UL << 28)346#define Py_TPFLAGS_DICT_SUBCLASS        (1UL << 29)347#define Py_TPFLAGS_BASE_EXC_SUBCLASS    (1UL << 30)348#define Py_TPFLAGS_TYPE_SUBCLASS        (1UL << 31)349 350#define Py_TPFLAGS_DEFAULT  ( \351                 Py_TPFLAGS_HAVE_STACKLESS_EXTENSION | \352                 Py_TPFLAGS_HAVE_VERSION_TAG | \353                0)354 355/* NOTE: The following flags reuse lower bits (removed as part of the356 * Python 3.0 transition). */357 358/* The following flag is kept for compatibility. Starting with 3.8,359 * binary compatibility of C extensions across feature releases of360 * Python is not supported anymore, except when using the stable ABI.361 */362 363/* Type structure has tp_finalize member (3.4) */364#define Py_TPFLAGS_HAVE_FINALIZE (1UL << 0)365 366 367/*368The macros Py_INCREF(op) and Py_DECREF(op) are used to increment or decrement369reference counts.  Py_DECREF calls the object's deallocator function when370the refcount falls to 0; for371objects that don't contain references to other objects or heap memory372this can be the standard function free().  Both macros can be used373wherever a void expression is allowed.  The argument must not be a374NULL pointer.  If it may be NULL, use Py_XINCREF/Py_XDECREF instead.375The macro _Py_NewReference(op) initialize reference counts to 1, and376in special builds (Py_REF_DEBUG, Py_TRACE_REFS) performs additional377bookkeeping appropriate to the special build.378 379We assume that the reference count field can never overflow; this can380be proven when the size of the field is the same as the pointer size, so381we ignore the possibility.  Provided a C int is at least 32 bits (which382is implicitly assumed in many parts of this code), that's enough for383about 2**31 references to an object.384 385XXX The following became out of date in Python 2.2, but I'm not sure386XXX what the full truth is now.  Certainly, heap-allocated type objects387XXX can and should be deallocated.388Type objects should never be deallocated; the type pointer in an object389is not considered to be a reference to the type object, to save390complications in the deallocation function.  (This is actually a391decision that's up to the implementer of each new type so if you want,392you can count such references to the type object.)393*/394 395#ifdef Py_REF_DEBUG396PyAPI_DATA(Py_ssize_t) _Py_RefTotal;397PyAPI_FUNC(void) _Py_NegativeRefcount(const char *filename, int lineno,398                                      PyObject *op);399#endif /* Py_REF_DEBUG */400 401PyAPI_FUNC(void) _Py_Dealloc(PyObject *);402 403static inline void _Py_INCREF(PyObject *op)404{405#ifdef Py_REF_DEBUG406    _Py_RefTotal++;407#endif408    op->ob_refcnt++;409}410 411#define Py_INCREF(op) _Py_INCREF(_PyObject_CAST(op))412 413static inline void _Py_DECREF(414#ifdef Py_REF_DEBUG415    const char *filename, int lineno,416#endif417    PyObject *op)418{419#ifdef Py_REF_DEBUG420    _Py_RefTotal--;421#endif422    if (--op->ob_refcnt != 0) {423#ifdef Py_REF_DEBUG424        if (op->ob_refcnt < 0) {425            _Py_NegativeRefcount(filename, lineno, op);426        }427#endif428    }429    else {430        _Py_Dealloc(op);431    }432}433 434#ifdef Py_REF_DEBUG435#  define Py_DECREF(op) _Py_DECREF(__FILE__, __LINE__, _PyObject_CAST(op))436#else437#  define Py_DECREF(op) _Py_DECREF(_PyObject_CAST(op))438#endif439 440 441/* Safely decref `op` and set `op` to NULL, especially useful in tp_clear442 * and tp_dealloc implementations.443 *444 * Note that "the obvious" code can be deadly:445 *446 *     Py_XDECREF(op);447 *     op = NULL;448 *449 * Typically, `op` is something like self->containee, and `self` is done450 * using its `containee` member.  In the code sequence above, suppose451 * `containee` is non-NULL with a refcount of 1.  Its refcount falls to452 * 0 on the first line, which can trigger an arbitrary amount of code,453 * possibly including finalizers (like __del__ methods or weakref callbacks)454 * coded in Python, which in turn can release the GIL and allow other threads455 * to run, etc.  Such code may even invoke methods of `self` again, or cause456 * cyclic gc to trigger, but-- oops! --self->containee still points to the457 * object being torn down, and it may be in an insane state while being torn458 * down.  This has in fact been a rich historic source of miserable (rare &459 * hard-to-diagnose) segfaulting (and other) bugs.460 *461 * The safe way is:462 *463 *      Py_CLEAR(op);464 *465 * That arranges to set `op` to NULL _before_ decref'ing, so that any code466 * triggered as a side-effect of `op` getting torn down no longer believes467 * `op` points to a valid object.468 *469 * There are cases where it's safe to use the naive code, but they're brittle.470 * For example, if `op` points to a Python integer, you know that destroying471 * one of those can't cause problems -- but in part that relies on that472 * Python integers aren't currently weakly referencable.  Best practice is473 * to use Py_CLEAR() even if you can't think of a reason for why you need to.474 */475#define Py_CLEAR(op)                            \476    do {                                        \477        PyObject *_py_tmp = _PyObject_CAST(op); \478        if (_py_tmp != NULL) {                  \479            (op) = NULL;                        \480            Py_DECREF(_py_tmp);                 \481        }                                       \482    } while (0)483 484/* Function to use in case the object pointer can be NULL: */485static inline void _Py_XINCREF(PyObject *op)486{487    if (op != NULL) {488        Py_INCREF(op);489    }490}491 492#define Py_XINCREF(op) _Py_XINCREF(_PyObject_CAST(op))493 494static inline void _Py_XDECREF(PyObject *op)495{496    if (op != NULL) {497        Py_DECREF(op);498    }499}500 501#define Py_XDECREF(op) _Py_XDECREF(_PyObject_CAST(op))502 503/*504These are provided as conveniences to Python runtime embedders, so that505they can have object code that is not dependent on Python compilation flags.506*/507PyAPI_FUNC(void) Py_IncRef(PyObject *);508PyAPI_FUNC(void) Py_DecRef(PyObject *);509 510/*511_Py_NoneStruct is an object of undefined type which can be used in contexts512where NULL (nil) is not suitable (since NULL often means 'error').513 514Don't forget to apply Py_INCREF() when returning this value!!!515*/516PyAPI_DATA(PyObject) _Py_NoneStruct; /* Don't use this directly */517#define Py_None (&_Py_NoneStruct)518 519/* Macro for returning Py_None from a function */520#define Py_RETURN_NONE return Py_INCREF(Py_None), Py_None521 522/*523Py_NotImplemented is a singleton used to signal that an operation is524not implemented for a given type combination.525*/526PyAPI_DATA(PyObject) _Py_NotImplementedStruct; /* Don't use this directly */527#define Py_NotImplemented (&_Py_NotImplementedStruct)528 529/* Macro for returning Py_NotImplemented from a function */530#define Py_RETURN_NOTIMPLEMENTED \531    return Py_INCREF(Py_NotImplemented), Py_NotImplemented532 533/* Rich comparison opcodes */534#define Py_LT 0535#define Py_LE 1536#define Py_EQ 2537#define Py_NE 3538#define Py_GT 4539#define Py_GE 5540 541/*542 * Macro for implementing rich comparisons543 *544 * Needs to be a macro because any C-comparable type can be used.545 */546#define Py_RETURN_RICHCOMPARE(val1, val2, op)                               \547    do {                                                                    \548        switch (op) {                                                       \549        case Py_EQ: if ((val1) == (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \550        case Py_NE: if ((val1) != (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \551        case Py_LT: if ((val1) < (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;   \552        case Py_GT: if ((val1) > (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;   \553        case Py_LE: if ((val1) <= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \554        case Py_GE: if ((val1) >= (val2)) Py_RETURN_TRUE; Py_RETURN_FALSE;  \555        default:                                                            \556            Py_UNREACHABLE();                                               \557        }                                                                   \558    } while (0)559 560 561/*562More conventions563================564 565Argument Checking566-----------------567 568Functions that take objects as arguments normally don't check for nil569arguments, but they do check the type of the argument, and return an570error if the function doesn't apply to the type.571 572Failure Modes573-------------574 575Functions may fail for a variety of reasons, including running out of576memory.  This is communicated to the caller in two ways: an error string577is set (see errors.h), and the function result differs: functions that578normally return a pointer return NULL for failure, functions returning579an integer return -1 (which could be a legal return value too!), and580other functions return 0 for success and -1 for failure.581Callers should always check for errors before using the result.  If582an error was set, the caller must either explicitly clear it, or pass583the error on to its caller.584 585Reference Counts586----------------587 588It takes a while to get used to the proper usage of reference counts.589 590Functions that create an object set the reference count to 1; such new591objects must be stored somewhere or destroyed again with Py_DECREF().592Some functions that 'store' objects, such as PyTuple_SetItem() and593PyList_SetItem(),594don't increment the reference count of the object, since the most595frequent use is to store a fresh object.  Functions that 'retrieve'596objects, such as PyTuple_GetItem() and PyDict_GetItemString(), also597don't increment598the reference count, since most frequently the object is only looked at599quickly.  Thus, to retrieve an object and store it again, the caller600must call Py_INCREF() explicitly.601 602NOTE: functions that 'consume' a reference count, like603PyList_SetItem(), consume the reference even if the object wasn't604successfully stored, to simplify error handling.605 606It seems attractive to make other functions that take an object as607argument consume a reference count; however, this may quickly get608confusing (even the current practice is already confusing).  Consider609it carefully, it may save lots of calls to Py_INCREF() and Py_DECREF() at610times.611*/612 613#ifndef Py_LIMITED_API614#  define Py_CPYTHON_OBJECT_H615#  include  "cpython/object.h"616#  undef Py_CPYTHON_OBJECT_H617#endif618 619 620static inline int621PyType_HasFeature(PyTypeObject *type, unsigned long feature)622{623    unsigned long flags;624#ifdef Py_LIMITED_API625    // PyTypeObject is opaque in the limited C API626    flags = PyType_GetFlags(type);627#else628    flags = type->tp_flags;629#endif630    return ((flags & feature) != 0);631}632 633#define PyType_FastSubclass(type, flag) PyType_HasFeature(type, flag)634 635static inline int _PyType_Check(PyObject *op) {636    return PyType_FastSubclass(Py_TYPE(op), Py_TPFLAGS_TYPE_SUBCLASS);637}638#define PyType_Check(op) _PyType_Check(_PyObject_CAST(op))639 640static inline int _PyType_CheckExact(PyObject *op) {641    return Py_IS_TYPE(op, &PyType_Type);642}643#define PyType_CheckExact(op) _PyType_CheckExact(_PyObject_CAST(op))644 645#ifdef __cplusplus646}647#endif648#endif /* !Py_OBJECT_H */649