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author | Georg Brandl <georg@python.org> | 2007-08-15 14:28:22 (GMT) |
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committer | Georg Brandl <georg@python.org> | 2007-08-15 14:28:22 (GMT) |
commit | 116aa62bf54a39697e25f21d6cf6799f7faa1349 (patch) | |
tree | 8db5729518ed4ca88e26f1e26cc8695151ca3eb3 /Doc/c-api/abstract.rst | |
parent | 739c01d47b9118d04e5722333f0e6b4d0c8bdd9e (diff) | |
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diff --git a/Doc/c-api/abstract.rst b/Doc/c-api/abstract.rst new file mode 100644 index 0000000..1a1ff13 --- /dev/null +++ b/Doc/c-api/abstract.rst @@ -0,0 +1,997 @@ +.. highlightlang:: c + + +.. _abstract: + +********************** +Abstract Objects Layer +********************** + +The functions in this chapter interact with Python objects regardless of their +type, or with wide classes of object types (e.g. all numerical types, or all +sequence types). When used on object types for which they do not apply, they +will raise a Python exception. + +It is not possible to use these functions on objects that are not properly +initialized, such as a list object that has been created by :cfunc:`PyList_New`, +but whose items have not been set to some non-\ ``NULL`` value yet. + + +.. _object: + +Object Protocol +=============== + + +.. cfunction:: int PyObject_Print(PyObject *o, FILE *fp, int flags) + + Print an object *o*, on file *fp*. Returns ``-1`` on error. The flags argument + is used to enable certain printing options. The only option currently supported + is :const:`Py_PRINT_RAW`; if given, the :func:`str` of the object is written + instead of the :func:`repr`. + + +.. cfunction:: int PyObject_HasAttrString(PyObject *o, const char *attr_name) + + Returns ``1`` if *o* has the attribute *attr_name*, and ``0`` otherwise. This + is equivalent to the Python expression ``hasattr(o, attr_name)``. This function + always succeeds. + + +.. cfunction:: PyObject* PyObject_GetAttrString(PyObject *o, const char *attr_name) + + Retrieve an attribute named *attr_name* from object *o*. Returns the attribute + value on success, or *NULL* on failure. This is the equivalent of the Python + expression ``o.attr_name``. + + +.. cfunction:: int PyObject_HasAttr(PyObject *o, PyObject *attr_name) + + Returns ``1`` if *o* has the attribute *attr_name*, and ``0`` otherwise. This + is equivalent to the Python expression ``hasattr(o, attr_name)``. This function + always succeeds. + + +.. cfunction:: PyObject* PyObject_GetAttr(PyObject *o, PyObject *attr_name) + + Retrieve an attribute named *attr_name* from object *o*. Returns the attribute + value on success, or *NULL* on failure. This is the equivalent of the Python + expression ``o.attr_name``. + + +.. cfunction:: int PyObject_SetAttrString(PyObject *o, const char *attr_name, PyObject *v) + + Set the value of the attribute named *attr_name*, for object *o*, to the value + *v*. Returns ``-1`` on failure. This is the equivalent of the Python statement + ``o.attr_name = v``. + + +.. cfunction:: int PyObject_SetAttr(PyObject *o, PyObject *attr_name, PyObject *v) + + Set the value of the attribute named *attr_name*, for object *o*, to the value + *v*. Returns ``-1`` on failure. This is the equivalent of the Python statement + ``o.attr_name = v``. + + +.. cfunction:: int PyObject_DelAttrString(PyObject *o, const char *attr_name) + + Delete attribute named *attr_name*, for object *o*. Returns ``-1`` on failure. + This is the equivalent of the Python statement: ``del o.attr_name``. + + +.. cfunction:: int PyObject_DelAttr(PyObject *o, PyObject *attr_name) + + Delete attribute named *attr_name*, for object *o*. Returns ``-1`` on failure. + This is the equivalent of the Python statement ``del o.attr_name``. + + +.. cfunction:: PyObject* PyObject_RichCompare(PyObject *o1, PyObject *o2, int opid) + + Compare the values of *o1* and *o2* using the operation specified by *opid*, + which must be one of :const:`Py_LT`, :const:`Py_LE`, :const:`Py_EQ`, + :const:`Py_NE`, :const:`Py_GT`, or :const:`Py_GE`, corresponding to ``<``, + ``<=``, ``==``, ``!=``, ``>``, or ``>=`` respectively. This is the equivalent of + the Python expression ``o1 op o2``, where ``op`` is the operator corresponding + to *opid*. Returns the value of the comparison on success, or *NULL* on failure. + + +.. cfunction:: int PyObject_RichCompareBool(PyObject *o1, PyObject *o2, int opid) + + Compare the values of *o1* and *o2* using the operation specified by *opid*, + which must be one of :const:`Py_LT`, :const:`Py_LE`, :const:`Py_EQ`, + :const:`Py_NE`, :const:`Py_GT`, or :const:`Py_GE`, corresponding to ``<``, + ``<=``, ``==``, ``!=``, ``>``, or ``>=`` respectively. Returns ``-1`` on error, + ``0`` if the result is false, ``1`` otherwise. This is the equivalent of the + Python expression ``o1 op o2``, where ``op`` is the operator corresponding to + *opid*. + + +.. cfunction:: int PyObject_Cmp(PyObject *o1, PyObject *o2, int *result) + + .. index:: builtin: cmp + + Compare the values of *o1* and *o2* using a routine provided by *o1*, if one + exists, otherwise with a routine provided by *o2*. The result of the comparison + is returned in *result*. Returns ``-1`` on failure. This is the equivalent of + the Python statement ``result = cmp(o1, o2)``. + + +.. cfunction:: int PyObject_Compare(PyObject *o1, PyObject *o2) + + .. index:: builtin: cmp + + Compare the values of *o1* and *o2* using a routine provided by *o1*, if one + exists, otherwise with a routine provided by *o2*. Returns the result of the + comparison on success. On error, the value returned is undefined; use + :cfunc:`PyErr_Occurred` to detect an error. This is equivalent to the Python + expression ``cmp(o1, o2)``. + + +.. cfunction:: PyObject* PyObject_Repr(PyObject *o) + + .. index:: builtin: repr + + Compute a string representation of object *o*. Returns the string + representation on success, *NULL* on failure. This is the equivalent of the + Python expression ``repr(o)``. Called by the :func:`repr` built-in function and + by reverse quotes. + + +.. cfunction:: PyObject* PyObject_Str(PyObject *o) + + .. index:: builtin: str + + Compute a string representation of object *o*. Returns the string + representation on success, *NULL* on failure. This is the equivalent of the + Python expression ``str(o)``. Called by the :func:`str` built-in function and + by the :keyword:`print` statement. + + +.. cfunction:: PyObject* PyObject_Unicode(PyObject *o) + + .. index:: builtin: unicode + + Compute a Unicode string representation of object *o*. Returns the Unicode + string representation on success, *NULL* on failure. This is the equivalent of + the Python expression ``unicode(o)``. Called by the :func:`unicode` built-in + function. + + +.. cfunction:: int PyObject_IsInstance(PyObject *inst, PyObject *cls) + + Returns ``1`` if *inst* is an instance of the class *cls* or a subclass of + *cls*, or ``0`` if not. On error, returns ``-1`` and sets an exception. If + *cls* is a type object rather than a class object, :cfunc:`PyObject_IsInstance` + returns ``1`` if *inst* is of type *cls*. If *cls* is a tuple, the check will + be done against every entry in *cls*. The result will be ``1`` when at least one + of the checks returns ``1``, otherwise it will be ``0``. If *inst* is not a + class instance and *cls* is neither a type object, nor a class object, nor a + tuple, *inst* must have a :attr:`__class__` attribute --- the class relationship + of the value of that attribute with *cls* will be used to determine the result + of this function. + + .. versionadded:: 2.1 + + .. versionchanged:: 2.2 + Support for a tuple as the second argument added. + +Subclass determination is done in a fairly straightforward way, but includes a +wrinkle that implementors of extensions to the class system may want to be aware +of. If :class:`A` and :class:`B` are class objects, :class:`B` is a subclass of +:class:`A` if it inherits from :class:`A` either directly or indirectly. If +either is not a class object, a more general mechanism is used to determine the +class relationship of the two objects. When testing if *B* is a subclass of +*A*, if *A* is *B*, :cfunc:`PyObject_IsSubclass` returns true. If *A* and *B* +are different objects, *B*'s :attr:`__bases__` attribute is searched in a +depth-first fashion for *A* --- the presence of the :attr:`__bases__` attribute +is considered sufficient for this determination. + + +.. cfunction:: int PyObject_IsSubclass(PyObject *derived, PyObject *cls) + + Returns ``1`` if the class *derived* is identical to or derived from the class + *cls*, otherwise returns ``0``. In case of an error, returns ``-1``. If *cls* + is a tuple, the check will be done against every entry in *cls*. The result will + be ``1`` when at least one of the checks returns ``1``, otherwise it will be + ``0``. If either *derived* or *cls* is not an actual class object (or tuple), + this function uses the generic algorithm described above. + + .. versionadded:: 2.1 + + .. versionchanged:: 2.3 + Older versions of Python did not support a tuple as the second argument. + + +.. cfunction:: int PyCallable_Check(PyObject *o) + + Determine if the object *o* is callable. Return ``1`` if the object is callable + and ``0`` otherwise. This function always succeeds. + + +.. cfunction:: PyObject* PyObject_Call(PyObject *callable_object, PyObject *args, PyObject *kw) + + Call a callable Python object *callable_object*, with arguments given by the + tuple *args*, and named arguments given by the dictionary *kw*. If no named + arguments are needed, *kw* may be *NULL*. *args* must not be *NULL*, use an + empty tuple if no arguments are needed. Returns the result of the call on + success, or *NULL* on failure. This is the equivalent of the Python expression + ``callable_object(*args, **kw)``. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyObject_CallObject(PyObject *callable_object, PyObject *args) + + Call a callable Python object *callable_object*, with arguments given by the + tuple *args*. If no arguments are needed, then *args* may be *NULL*. Returns + the result of the call on success, or *NULL* on failure. This is the equivalent + of the Python expression ``callable_object(*args)``. + + +.. cfunction:: PyObject* PyObject_CallFunction(PyObject *callable, char *format, ...) + + Call a callable Python object *callable*, with a variable number of C arguments. + The C arguments are described using a :cfunc:`Py_BuildValue` style format + string. The format may be *NULL*, indicating that no arguments are provided. + Returns the result of the call on success, or *NULL* on failure. This is the + equivalent of the Python expression ``callable(*args)``. Note that if you only + pass :ctype:`PyObject \*` args, :cfunc:`PyObject_CallFunctionObjArgs` is a + faster alternative. + + +.. cfunction:: PyObject* PyObject_CallMethod(PyObject *o, char *method, char *format, ...) + + Call the method named *method* of object *o* with a variable number of C + arguments. The C arguments are described by a :cfunc:`Py_BuildValue` format + string that should produce a tuple. The format may be *NULL*, indicating that + no arguments are provided. Returns the result of the call on success, or *NULL* + on failure. This is the equivalent of the Python expression ``o.method(args)``. + Note that if you only pass :ctype:`PyObject \*` args, + :cfunc:`PyObject_CallMethodObjArgs` is a faster alternative. + + +.. cfunction:: PyObject* PyObject_CallFunctionObjArgs(PyObject *callable, ..., NULL) + + Call a callable Python object *callable*, with a variable number of + :ctype:`PyObject\*` arguments. The arguments are provided as a variable number + of parameters followed by *NULL*. Returns the result of the call on success, or + *NULL* on failure. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyObject_CallMethodObjArgs(PyObject *o, PyObject *name, ..., NULL) + + Calls a method of the object *o*, where the name of the method is given as a + Python string object in *name*. It is called with a variable number of + :ctype:`PyObject\*` arguments. The arguments are provided as a variable number + of parameters followed by *NULL*. Returns the result of the call on success, or + *NULL* on failure. + + .. versionadded:: 2.2 + + +.. cfunction:: long PyObject_Hash(PyObject *o) + + .. index:: builtin: hash + + Compute and return the hash value of an object *o*. On failure, return ``-1``. + This is the equivalent of the Python expression ``hash(o)``. + + +.. cfunction:: int PyObject_IsTrue(PyObject *o) + + Returns ``1`` if the object *o* is considered to be true, and ``0`` otherwise. + This is equivalent to the Python expression ``not not o``. On failure, return + ``-1``. + + +.. cfunction:: int PyObject_Not(PyObject *o) + + Returns ``0`` if the object *o* is considered to be true, and ``1`` otherwise. + This is equivalent to the Python expression ``not o``. On failure, return + ``-1``. + + +.. cfunction:: PyObject* PyObject_Type(PyObject *o) + + .. index:: builtin: type + + When *o* is non-*NULL*, returns a type object corresponding to the object type + of object *o*. On failure, raises :exc:`SystemError` and returns *NULL*. This + is equivalent to the Python expression ``type(o)``. This function increments the + reference count of the return value. There's really no reason to use this + function instead of the common expression ``o->ob_type``, which returns a + pointer of type :ctype:`PyTypeObject\*`, except when the incremented reference + count is needed. + + +.. cfunction:: int PyObject_TypeCheck(PyObject *o, PyTypeObject *type) + + Return true if the object *o* is of type *type* or a subtype of *type*. Both + parameters must be non-*NULL*. + + .. versionadded:: 2.2 + + +.. cfunction:: Py_ssize_t PyObject_Length(PyObject *o) + Py_ssize_t PyObject_Size(PyObject *o) + + .. index:: builtin: len + + Return the length of object *o*. If the object *o* provides either the sequence + and mapping protocols, the sequence length is returned. On error, ``-1`` is + returned. This is the equivalent to the Python expression ``len(o)``. + + +.. cfunction:: PyObject* PyObject_GetItem(PyObject *o, PyObject *key) + + Return element of *o* corresponding to the object *key* or *NULL* on failure. + This is the equivalent of the Python expression ``o[key]``. + + +.. cfunction:: int PyObject_SetItem(PyObject *o, PyObject *key, PyObject *v) + + Map the object *key* to the value *v*. Returns ``-1`` on failure. This is the + equivalent of the Python statement ``o[key] = v``. + + +.. cfunction:: int PyObject_DelItem(PyObject *o, PyObject *key) + + Delete the mapping for *key* from *o*. Returns ``-1`` on failure. This is the + equivalent of the Python statement ``del o[key]``. + + +.. cfunction:: int PyObject_AsFileDescriptor(PyObject *o) + + Derives a file-descriptor from a Python object. If the object is an integer or + long integer, its value is returned. If not, the object's :meth:`fileno` method + is called if it exists; the method must return an integer or long integer, which + is returned as the file descriptor value. Returns ``-1`` on failure. + + +.. cfunction:: PyObject* PyObject_Dir(PyObject *o) + + This is equivalent to the Python expression ``dir(o)``, returning a (possibly + empty) list of strings appropriate for the object argument, or *NULL* if there + was an error. If the argument is *NULL*, this is like the Python ``dir()``, + returning the names of the current locals; in this case, if no execution frame + is active then *NULL* is returned but :cfunc:`PyErr_Occurred` will return false. + + +.. cfunction:: PyObject* PyObject_GetIter(PyObject *o) + + This is equivalent to the Python expression ``iter(o)``. It returns a new + iterator for the object argument, or the object itself if the object is already + an iterator. Raises :exc:`TypeError` and returns *NULL* if the object cannot be + iterated. + + +.. _number: + +Number Protocol +=============== + + +.. cfunction:: int PyNumber_Check(PyObject *o) + + Returns ``1`` if the object *o* provides numeric protocols, and false otherwise. + This function always succeeds. + + +.. cfunction:: PyObject* PyNumber_Add(PyObject *o1, PyObject *o2) + + Returns the result of adding *o1* and *o2*, or *NULL* on failure. This is the + equivalent of the Python expression ``o1 + o2``. + + +.. cfunction:: PyObject* PyNumber_Subtract(PyObject *o1, PyObject *o2) + + Returns the result of subtracting *o2* from *o1*, or *NULL* on failure. This is + the equivalent of the Python expression ``o1 - o2``. + + +.. cfunction:: PyObject* PyNumber_Multiply(PyObject *o1, PyObject *o2) + + Returns the result of multiplying *o1* and *o2*, or *NULL* on failure. This is + the equivalent of the Python expression ``o1 * o2``. + + +.. cfunction:: PyObject* PyNumber_Divide(PyObject *o1, PyObject *o2) + + Returns the result of dividing *o1* by *o2*, or *NULL* on failure. This is the + equivalent of the Python expression ``o1 / o2``. + + +.. cfunction:: PyObject* PyNumber_FloorDivide(PyObject *o1, PyObject *o2) + + Return the floor of *o1* divided by *o2*, or *NULL* on failure. This is + equivalent to the "classic" division of integers. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyNumber_TrueDivide(PyObject *o1, PyObject *o2) + + Return a reasonable approximation for the mathematical value of *o1* divided by + *o2*, or *NULL* on failure. The return value is "approximate" because binary + floating point numbers are approximate; it is not possible to represent all real + numbers in base two. This function can return a floating point value when + passed two integers. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyNumber_Remainder(PyObject *o1, PyObject *o2) + + Returns the remainder of dividing *o1* by *o2*, or *NULL* on failure. This is + the equivalent of the Python expression ``o1 % o2``. + + +.. cfunction:: PyObject* PyNumber_Divmod(PyObject *o1, PyObject *o2) + + .. index:: builtin: divmod + + See the built-in function :func:`divmod`. Returns *NULL* on failure. This is + the equivalent of the Python expression ``divmod(o1, o2)``. + + +.. cfunction:: PyObject* PyNumber_Power(PyObject *o1, PyObject *o2, PyObject *o3) + + .. index:: builtin: pow + + See the built-in function :func:`pow`. Returns *NULL* on failure. This is the + equivalent of the Python expression ``pow(o1, o2, o3)``, where *o3* is optional. + If *o3* is to be ignored, pass :cdata:`Py_None` in its place (passing *NULL* for + *o3* would cause an illegal memory access). + + +.. cfunction:: PyObject* PyNumber_Negative(PyObject *o) + + Returns the negation of *o* on success, or *NULL* on failure. This is the + equivalent of the Python expression ``-o``. + + +.. cfunction:: PyObject* PyNumber_Positive(PyObject *o) + + Returns *o* on success, or *NULL* on failure. This is the equivalent of the + Python expression ``+o``. + + +.. cfunction:: PyObject* PyNumber_Absolute(PyObject *o) + + .. index:: builtin: abs + + Returns the absolute value of *o*, or *NULL* on failure. This is the equivalent + of the Python expression ``abs(o)``. + + +.. cfunction:: PyObject* PyNumber_Invert(PyObject *o) + + Returns the bitwise negation of *o* on success, or *NULL* on failure. This is + the equivalent of the Python expression ``~o``. + + +.. cfunction:: PyObject* PyNumber_Lshift(PyObject *o1, PyObject *o2) + + Returns the result of left shifting *o1* by *o2* on success, or *NULL* on + failure. This is the equivalent of the Python expression ``o1 << o2``. + + +.. cfunction:: PyObject* PyNumber_Rshift(PyObject *o1, PyObject *o2) + + Returns the result of right shifting *o1* by *o2* on success, or *NULL* on + failure. This is the equivalent of the Python expression ``o1 >> o2``. + + +.. cfunction:: PyObject* PyNumber_And(PyObject *o1, PyObject *o2) + + Returns the "bitwise and" of *o1* and *o2* on success and *NULL* on failure. + This is the equivalent of the Python expression ``o1 & o2``. + + +.. cfunction:: PyObject* PyNumber_Xor(PyObject *o1, PyObject *o2) + + Returns the "bitwise exclusive or" of *o1* by *o2* on success, or *NULL* on + failure. This is the equivalent of the Python expression ``o1 ^ o2``. + + +.. cfunction:: PyObject* PyNumber_Or(PyObject *o1, PyObject *o2) + + Returns the "bitwise or" of *o1* and *o2* on success, or *NULL* on failure. + This is the equivalent of the Python expression ``o1 | o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceAdd(PyObject *o1, PyObject *o2) + + Returns the result of adding *o1* and *o2*, or *NULL* on failure. The operation + is done *in-place* when *o1* supports it. This is the equivalent of the Python + statement ``o1 += o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceSubtract(PyObject *o1, PyObject *o2) + + Returns the result of subtracting *o2* from *o1*, or *NULL* on failure. The + operation is done *in-place* when *o1* supports it. This is the equivalent of + the Python statement ``o1 -= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceMultiply(PyObject *o1, PyObject *o2) + + Returns the result of multiplying *o1* and *o2*, or *NULL* on failure. The + operation is done *in-place* when *o1* supports it. This is the equivalent of + the Python statement ``o1 *= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceDivide(PyObject *o1, PyObject *o2) + + Returns the result of dividing *o1* by *o2*, or *NULL* on failure. The + operation is done *in-place* when *o1* supports it. This is the equivalent of + the Python statement ``o1 /= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceFloorDivide(PyObject *o1, PyObject *o2) + + Returns the mathematical floor of dividing *o1* by *o2*, or *NULL* on failure. + The operation is done *in-place* when *o1* supports it. This is the equivalent + of the Python statement ``o1 //= o2``. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyNumber_InPlaceTrueDivide(PyObject *o1, PyObject *o2) + + Return a reasonable approximation for the mathematical value of *o1* divided by + *o2*, or *NULL* on failure. The return value is "approximate" because binary + floating point numbers are approximate; it is not possible to represent all real + numbers in base two. This function can return a floating point value when + passed two integers. The operation is done *in-place* when *o1* supports it. + + .. versionadded:: 2.2 + + +.. cfunction:: PyObject* PyNumber_InPlaceRemainder(PyObject *o1, PyObject *o2) + + Returns the remainder of dividing *o1* by *o2*, or *NULL* on failure. The + operation is done *in-place* when *o1* supports it. This is the equivalent of + the Python statement ``o1 %= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlacePower(PyObject *o1, PyObject *o2, PyObject *o3) + + .. index:: builtin: pow + + See the built-in function :func:`pow`. Returns *NULL* on failure. The operation + is done *in-place* when *o1* supports it. This is the equivalent of the Python + statement ``o1 **= o2`` when o3 is :cdata:`Py_None`, or an in-place variant of + ``pow(o1, o2, o3)`` otherwise. If *o3* is to be ignored, pass :cdata:`Py_None` + in its place (passing *NULL* for *o3* would cause an illegal memory access). + + +.. cfunction:: PyObject* PyNumber_InPlaceLshift(PyObject *o1, PyObject *o2) + + Returns the result of left shifting *o1* by *o2* on success, or *NULL* on + failure. The operation is done *in-place* when *o1* supports it. This is the + equivalent of the Python statement ``o1 <<= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceRshift(PyObject *o1, PyObject *o2) + + Returns the result of right shifting *o1* by *o2* on success, or *NULL* on + failure. The operation is done *in-place* when *o1* supports it. This is the + equivalent of the Python statement ``o1 >>= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceAnd(PyObject *o1, PyObject *o2) + + Returns the "bitwise and" of *o1* and *o2* on success and *NULL* on failure. The + operation is done *in-place* when *o1* supports it. This is the equivalent of + the Python statement ``o1 &= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceXor(PyObject *o1, PyObject *o2) + + Returns the "bitwise exclusive or" of *o1* by *o2* on success, or *NULL* on + failure. The operation is done *in-place* when *o1* supports it. This is the + equivalent of the Python statement ``o1 ^= o2``. + + +.. cfunction:: PyObject* PyNumber_InPlaceOr(PyObject *o1, PyObject *o2) + + Returns the "bitwise or" of *o1* and *o2* on success, or *NULL* on failure. The + operation is done *in-place* when *o1* supports it. This is the equivalent of + the Python statement ``o1 |= o2``. + + +.. cfunction:: PyObject* PyNumber_Int(PyObject *o) + + .. index:: builtin: int + + Returns the *o* converted to an integer object on success, or *NULL* on failure. + If the argument is outside the integer range a long object will be returned + instead. This is the equivalent of the Python expression ``int(o)``. + + +.. cfunction:: PyObject* PyNumber_Long(PyObject *o) + + .. index:: builtin: long + + Returns the *o* converted to a long integer object on success, or *NULL* on + failure. This is the equivalent of the Python expression ``long(o)``. + + +.. cfunction:: PyObject* PyNumber_Float(PyObject *o) + + .. index:: builtin: float + + Returns the *o* converted to a float object on success, or *NULL* on failure. + This is the equivalent of the Python expression ``float(o)``. + + +.. cfunction:: PyObject* PyNumber_Index(PyObject *o) + + Returns the *o* converted to a Python int or long on success or *NULL* with a + TypeError exception raised on failure. + + .. versionadded:: 2.5 + + +.. cfunction:: Py_ssize_t PyNumber_AsSsize_t(PyObject *o, PyObject *exc) + + Returns *o* converted to a Py_ssize_t value if *o* can be interpreted as an + integer. If *o* can be converted to a Python int or long but the attempt to + convert to a Py_ssize_t value would raise an :exc:`OverflowError`, then the + *exc* argument is the type of exception that will be raised (usually + :exc:`IndexError` or :exc:`OverflowError`). If *exc* is *NULL*, then the + exception is cleared and the value is clipped to *PY_SSIZE_T_MIN* for a negative + integer or *PY_SSIZE_T_MAX* for a positive integer. + + .. versionadded:: 2.5 + + +.. cfunction:: int PyIndex_Check(PyObject *o) + + Returns True if *o* is an index integer (has the nb_index slot of the + tp_as_number structure filled in). + + .. versionadded:: 2.5 + + +.. _sequence: + +Sequence Protocol +================= + + +.. cfunction:: int PySequence_Check(PyObject *o) + + Return ``1`` if the object provides sequence protocol, and ``0`` otherwise. + This function always succeeds. + + +.. cfunction:: Py_ssize_t PySequence_Size(PyObject *o) + + .. index:: builtin: len + + Returns the number of objects in sequence *o* on success, and ``-1`` on failure. + For objects that do not provide sequence protocol, this is equivalent to the + Python expression ``len(o)``. + + +.. cfunction:: Py_ssize_t PySequence_Length(PyObject *o) + + Alternate name for :cfunc:`PySequence_Size`. + + +.. cfunction:: PyObject* PySequence_Concat(PyObject *o1, PyObject *o2) + + Return the concatenation of *o1* and *o2* on success, and *NULL* on failure. + This is the equivalent of the Python expression ``o1 + o2``. + + +.. cfunction:: PyObject* PySequence_Repeat(PyObject *o, Py_ssize_t count) + + Return the result of repeating sequence object *o* *count* times, or *NULL* on + failure. This is the equivalent of the Python expression ``o * count``. + + +.. cfunction:: PyObject* PySequence_InPlaceConcat(PyObject *o1, PyObject *o2) + + Return the concatenation of *o1* and *o2* on success, and *NULL* on failure. + The operation is done *in-place* when *o1* supports it. This is the equivalent + of the Python expression ``o1 += o2``. + + +.. cfunction:: PyObject* PySequence_InPlaceRepeat(PyObject *o, Py_ssize_t count) + + Return the result of repeating sequence object *o* *count* times, or *NULL* on + failure. The operation is done *in-place* when *o* supports it. This is the + equivalent of the Python expression ``o *= count``. + + +.. cfunction:: PyObject* PySequence_GetItem(PyObject *o, Py_ssize_t i) + + Return the *i*th element of *o*, or *NULL* on failure. This is the equivalent of + the Python expression ``o[i]``. + + +.. cfunction:: PyObject* PySequence_GetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2) + + Return the slice of sequence object *o* between *i1* and *i2*, or *NULL* on + failure. This is the equivalent of the Python expression ``o[i1:i2]``. + + +.. cfunction:: int PySequence_SetItem(PyObject *o, Py_ssize_t i, PyObject *v) + + Assign object *v* to the *i*th element of *o*. Returns ``-1`` on failure. This + is the equivalent of the Python statement ``o[i] = v``. This function *does + not* steal a reference to *v*. + + +.. cfunction:: int PySequence_DelItem(PyObject *o, Py_ssize_t i) + + Delete the *i*th element of object *o*. Returns ``-1`` on failure. This is the + equivalent of the Python statement ``del o[i]``. + + +.. cfunction:: int PySequence_SetSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2, PyObject *v) + + Assign the sequence object *v* to the slice in sequence object *o* from *i1* to + *i2*. This is the equivalent of the Python statement ``o[i1:i2] = v``. + + +.. cfunction:: int PySequence_DelSlice(PyObject *o, Py_ssize_t i1, Py_ssize_t i2) + + Delete the slice in sequence object *o* from *i1* to *i2*. Returns ``-1`` on + failure. This is the equivalent of the Python statement ``del o[i1:i2]``. + + +.. cfunction:: Py_ssize_t PySequence_Count(PyObject *o, PyObject *value) + + Return the number of occurrences of *value* in *o*, that is, return the number + of keys for which ``o[key] == value``. On failure, return ``-1``. This is + equivalent to the Python expression ``o.count(value)``. + + +.. cfunction:: int PySequence_Contains(PyObject *o, PyObject *value) + + Determine if *o* contains *value*. If an item in *o* is equal to *value*, + return ``1``, otherwise return ``0``. On error, return ``-1``. This is + equivalent to the Python expression ``value in o``. + + +.. cfunction:: Py_ssize_t PySequence_Index(PyObject *o, PyObject *value) + + Return the first index *i* for which ``o[i] == value``. On error, return + ``-1``. This is equivalent to the Python expression ``o.index(value)``. + + +.. cfunction:: PyObject* PySequence_List(PyObject *o) + + Return a list object with the same contents as the arbitrary sequence *o*. The + returned list is guaranteed to be new. + + +.. cfunction:: PyObject* PySequence_Tuple(PyObject *o) + + .. index:: builtin: tuple + + Return a tuple object with the same contents as the arbitrary sequence *o* or + *NULL* on failure. If *o* is a tuple, a new reference will be returned, + otherwise a tuple will be constructed with the appropriate contents. This is + equivalent to the Python expression ``tuple(o)``. + + +.. cfunction:: PyObject* PySequence_Fast(PyObject *o, const char *m) + + Returns the sequence *o* as a tuple, unless it is already a tuple or list, in + which case *o* is returned. Use :cfunc:`PySequence_Fast_GET_ITEM` to access the + members of the result. Returns *NULL* on failure. If the object is not a + sequence, raises :exc:`TypeError` with *m* as the message text. + + +.. cfunction:: PyObject* PySequence_Fast_GET_ITEM(PyObject *o, Py_ssize_t i) + + Return the *i*th element of *o*, assuming that *o* was returned by + :cfunc:`PySequence_Fast`, *o* is not *NULL*, and that *i* is within bounds. + + +.. cfunction:: PyObject** PySequence_Fast_ITEMS(PyObject *o) + + Return the underlying array of PyObject pointers. Assumes that *o* was returned + by :cfunc:`PySequence_Fast` and *o* is not *NULL*. + + .. versionadded:: 2.4 + + +.. cfunction:: PyObject* PySequence_ITEM(PyObject *o, Py_ssize_t i) + + Return the *i*th element of *o* or *NULL* on failure. Macro form of + :cfunc:`PySequence_GetItem` but without checking that + :cfunc:`PySequence_Check(o)` is true and without adjustment for negative + indices. + + .. versionadded:: 2.3 + + +.. cfunction:: Py_ssize_t PySequence_Fast_GET_SIZE(PyObject *o) + + Returns the length of *o*, assuming that *o* was returned by + :cfunc:`PySequence_Fast` and that *o* is not *NULL*. The size can also be + gotten by calling :cfunc:`PySequence_Size` on *o*, but + :cfunc:`PySequence_Fast_GET_SIZE` is faster because it can assume *o* is a list + or tuple. + + +.. _mapping: + +Mapping Protocol +================ + + +.. cfunction:: int PyMapping_Check(PyObject *o) + + Return ``1`` if the object provides mapping protocol, and ``0`` otherwise. This + function always succeeds. + + +.. cfunction:: Py_ssize_t PyMapping_Length(PyObject *o) + + .. index:: builtin: len + + Returns the number of keys in object *o* on success, and ``-1`` on failure. For + objects that do not provide mapping protocol, this is equivalent to the Python + expression ``len(o)``. + + +.. cfunction:: int PyMapping_DelItemString(PyObject *o, char *key) + + Remove the mapping for object *key* from the object *o*. Return ``-1`` on + failure. This is equivalent to the Python statement ``del o[key]``. + + +.. cfunction:: int PyMapping_DelItem(PyObject *o, PyObject *key) + + Remove the mapping for object *key* from the object *o*. Return ``-1`` on + failure. This is equivalent to the Python statement ``del o[key]``. + + +.. cfunction:: int PyMapping_HasKeyString(PyObject *o, char *key) + + On success, return ``1`` if the mapping object has the key *key* and ``0`` + otherwise. This is equivalent to the Python expression ``o.has_key(key)``. + This function always succeeds. + + +.. cfunction:: int PyMapping_HasKey(PyObject *o, PyObject *key) + + Return ``1`` if the mapping object has the key *key* and ``0`` otherwise. This + is equivalent to the Python expression ``o.has_key(key)``. This function always + succeeds. + + +.. cfunction:: PyObject* PyMapping_Keys(PyObject *o) + + On success, return a list of the keys in object *o*. On failure, return *NULL*. + This is equivalent to the Python expression ``o.keys()``. + + +.. cfunction:: PyObject* PyMapping_Values(PyObject *o) + + On success, return a list of the values in object *o*. On failure, return + *NULL*. This is equivalent to the Python expression ``o.values()``. + + +.. cfunction:: PyObject* PyMapping_Items(PyObject *o) + + On success, return a list of the items in object *o*, where each item is a tuple + containing a key-value pair. On failure, return *NULL*. This is equivalent to + the Python expression ``o.items()``. + + +.. cfunction:: PyObject* PyMapping_GetItemString(PyObject *o, char *key) + + Return element of *o* corresponding to the object *key* or *NULL* on failure. + This is the equivalent of the Python expression ``o[key]``. + + +.. cfunction:: int PyMapping_SetItemString(PyObject *o, char *key, PyObject *v) + + Map the object *key* to the value *v* in object *o*. Returns ``-1`` on failure. + This is the equivalent of the Python statement ``o[key] = v``. + + +.. _iterator: + +Iterator Protocol +================= + +.. versionadded:: 2.2 + +There are only a couple of functions specifically for working with iterators. + + +.. cfunction:: int PyIter_Check(PyObject *o) + + Return true if the object *o* supports the iterator protocol. + + +.. cfunction:: PyObject* PyIter_Next(PyObject *o) + + Return the next value from the iteration *o*. If the object is an iterator, + this retrieves the next value from the iteration, and returns *NULL* with no + exception set if there are no remaining items. If the object is not an + iterator, :exc:`TypeError` is raised, or if there is an error in retrieving the + item, returns *NULL* and passes along the exception. + +To write a loop which iterates over an iterator, the C code should look +something like this:: + + PyObject *iterator = PyObject_GetIter(obj); + PyObject *item; + + if (iterator == NULL) { + /* propagate error */ + } + + while (item = PyIter_Next(iterator)) { + /* do something with item */ + ... + /* release reference when done */ + Py_DECREF(item); + } + + Py_DECREF(iterator); + + if (PyErr_Occurred()) { + /* propagate error */ + } + else { + /* continue doing useful work */ + } + + +.. _abstract-buffer: + +Buffer Protocol +=============== + + +.. cfunction:: int PyObject_AsCharBuffer(PyObject *obj, const char **buffer, Py_ssize_t *buffer_len) + + Returns a pointer to a read-only memory location useable as character- based + input. The *obj* argument must support the single-segment character buffer + interface. On success, returns ``0``, sets *buffer* to the memory location and + *buffer_len* to the buffer length. Returns ``-1`` and sets a :exc:`TypeError` + on error. + + .. versionadded:: 1.6 + + +.. cfunction:: int PyObject_AsReadBuffer(PyObject *obj, const void **buffer, Py_ssize_t *buffer_len) + + Returns a pointer to a read-only memory location containing arbitrary data. The + *obj* argument must support the single-segment readable buffer interface. On + success, returns ``0``, sets *buffer* to the memory location and *buffer_len* to + the buffer length. Returns ``-1`` and sets a :exc:`TypeError` on error. + + .. versionadded:: 1.6 + + +.. cfunction:: int PyObject_CheckReadBuffer(PyObject *o) + + Returns ``1`` if *o* supports the single-segment readable buffer interface. + Otherwise returns ``0``. + + .. versionadded:: 2.2 + + +.. cfunction:: int PyObject_AsWriteBuffer(PyObject *obj, void **buffer, Py_ssize_t *buffer_len) + + Returns a pointer to a writeable memory location. The *obj* argument must + support the single-segment, character buffer interface. On success, returns + ``0``, sets *buffer* to the memory location and *buffer_len* to the buffer + length. Returns ``-1`` and sets a :exc:`TypeError` on error. + + .. versionadded:: 1.6 + |