Object Protocol¶

intPyObject_Print(PyObject *o, FILE *fp, int flags)¶

Print an objecto, on filefp. Returns-1 on error. The flags argumentis used to enable certain printing options. The only option currently supportedisPy_PRINT_RAW; if given, thestr() of the object is writteninstead of therepr().

intPyObject_HasAttr(PyObject *o,PyObject *attr_name)¶

Returns1 ifo has the attributeattr_name, and0 otherwise. Thisis equivalent to the Python expressionhasattr(o,attr_name). This functionalways succeeds.

intPyObject_HasAttrString(PyObject *o, const char *attr_name)¶

Returns1 ifo has the attributeattr_name, and0 otherwise. Thisis equivalent to the Python expressionhasattr(o,attr_name). This functionalways succeeds.

PyObject*PyObject_GetAttr(PyObject *o,PyObject *attr_name)¶

Return value: New reference.

Retrieve an attribute namedattr_name from objecto. Returns the attributevalue on success, orNULL on failure. This is the equivalent of the Pythonexpressiono.attr_name.

PyObject*PyObject_GetAttrString(PyObject *o, const char *attr_name)¶

Return value: New reference.

Retrieve an attribute namedattr_name from objecto. Returns the attributevalue on success, orNULL on failure. This is the equivalent of the Pythonexpressiono.attr_name.

PyObject*PyObject_GenericGetAttr(PyObject *o,PyObject *name)¶

Generic attribute getter function that is meant to be put into a typeobject’stp_getattro slot. It looks for a descriptor in the dictionaryof classes in the object’s MRO as well as an attribute in the object’s__dict__ (if present). As outlined inImplementing Descriptors,data descriptors take preference over instance attributes, while non-datadescriptors don’t. Otherwise, anAttributeError is raised.

intPyObject_SetAttr(PyObject *o,PyObject *attr_name,PyObject *v)¶

Set the value of the attribute namedattr_name, for objecto, to the valuev. Raise an exception and return-1 on failure;return0 on success. This is the equivalent of the Python statemento.attr_name=v.

Ifv isNULL, the attribute is deleted, however this feature isdeprecated in favour of usingPyObject_DelAttr().

intPyObject_SetAttrString(PyObject *o, const char *attr_name,PyObject *v)¶

Set the value of the attribute namedattr_name, for objecto, to the valuev. Raise an exception and return-1 on failure;return0 on success. This is the equivalent of the Python statemento.attr_name=v.

Ifv isNULL, the attribute is deleted, however this feature isdeprecated in favour of usingPyObject_DelAttrString().

intPyObject_GenericSetAttr(PyObject *o,PyObject *name,PyObject *value)¶

Generic attribute setter and deleter function that is meantto be put into a type object’stp_setattroslot. It looks for a data descriptor in thedictionary of classes in the object’s MRO, and if found it takes preferenceover setting or deleting the attribute in the instance dictionary. Otherwise, theattribute is set or deleted in the object’s__dict__ (if present).On success,0 is returned, otherwise anAttributeErroris raised and-1 is returned.

intPyObject_DelAttr(PyObject *o,PyObject *attr_name)¶

Delete attribute namedattr_name, for objecto. Returns-1 on failure.This is the equivalent of the Python statementdelo.attr_name.

intPyObject_DelAttrString(PyObject *o, const char *attr_name)¶

Delete attribute namedattr_name, for objecto. Returns-1 on failure.This is the equivalent of the Python statementdelo.attr_name.

PyObject*PyObject_RichCompare(PyObject *o1,PyObject *o2, int opid)¶

Return value: New reference.

Compare the values ofo1 ando2 using the operation specified byopid,which must be one ofPy_LT,Py_LE,Py_EQ,Py_NE,Py_GT, orPy_GE, corresponding to<,<=,==,!=,>, or>= respectively. This is the equivalent ofthe Python expressiono1opo2, whereop is the operator correspondingtoopid. Returns the value of the comparison on success, orNULL on failure.

intPyObject_RichCompareBool(PyObject *o1,PyObject *o2, int opid)¶

Compare the values ofo1 ando2 using the operation specified byopid,which must be one ofPy_LT,Py_LE,Py_EQ,Py_NE,Py_GT, orPy_GE, corresponding to<,<=,==,!=,>, or>= respectively. Returns-1 on error,0 if the result is false,1 otherwise. This is the equivalent of thePython expressiono1opo2, whereop is the operator corresponding toopid.

intPyObject_Cmp(PyObject *o1,PyObject *o2, int *result)¶

Compare the values ofo1 ando2 using a routine provided byo1, if oneexists, otherwise with a routine provided byo2. The result of the comparisonis returned inresult. Returns-1 on failure. This is the equivalent ofthe Python statementresult=cmp(o1,o2).

intPyObject_Compare(PyObject *o1,PyObject *o2)¶

Compare the values ofo1 ando2 using a routine provided byo1, if oneexists, otherwise with a routine provided byo2. Returns the result of thecomparison on success. On error, the value returned is undefined; usePyErr_Occurred() to detect an error. This is equivalent to the Pythonexpressioncmp(o1,o2).

PyObject*PyObject_Repr(PyObject *o)¶

Return value: New reference.

Compute a string representation of objecto. Returns the stringrepresentation on success,NULL on failure. This is the equivalent of thePython expressionrepr(o). Called by therepr() built-in function andby reverse quotes.

PyObject*PyObject_Str(PyObject *o)¶

Return value: New reference.

Compute a string representation of objecto. Returns the stringrepresentation on success,NULL on failure. This is the equivalent of thePython expressionstr(o). Called by thestr() built-in function andby theprint statement.

PyObject*PyObject_Bytes(PyObject *o)¶

Compute a bytes representation of objecto. In 2.x, this is just an aliasforPyObject_Str().

PyObject*PyObject_Unicode(PyObject *o)¶

Return value: New reference.

Compute a Unicode string representation of objecto. Returns the Unicodestring representation on success,NULL on failure. This is the equivalent ofthe Python expressionunicode(o). Called by theunicode() built-infunction.

intPyObject_IsInstance(PyObject *inst,PyObject *cls)¶

Returns1 ifinst is an instance of the classcls or a subclass ofcls, or0 if not. On error, returns-1 and sets an exception. Ifcls is a type object rather than a class object,PyObject_IsInstance()returns1 ifinst is of typecls. Ifcls is a tuple, the check willbe done against every entry incls. The result will be1 when at least oneof the checks returns1, otherwise it will be0. Ifinst is not aclass instance andcls is neither a type object, nor a class object, nor atuple,inst must have a__class__ attribute — theclass relationship of the value of that attribute withcls will be usedto determine the result of this function.

New in version 2.1.

Changed in version 2.2:Support for a tuple as the second argument added.

Subclass determination is done in a fairly straightforward way, but includes awrinkle that implementors of extensions to the class system may want to be awareof. IfA andB are class objects,B is a subclass ofA if it inherits fromA either directly or indirectly. Ifeither is not a class object, a more general mechanism is used to determine theclass relationship of the two objects. When testing ifB is a subclass ofA, ifA isB,PyObject_IsSubclass() returns true. IfA andBare different objects,B’s__bases__ attribute is searched ina depth-first fashion forA — the presence of the__bases__attribute is considered sufficient for this determination.

intPyObject_IsSubclass(PyObject *derived,PyObject *cls)¶

Returns1 if the classderived is identical to or derived from the classcls, otherwise returns0. In case of an error, returns-1. Ifclsis a tuple, the check will be done against every entry incls. The result willbe1 when at least one of the checks returns1, otherwise it will be0. If eitherderived orcls is not an actual class object (or tuple),this function uses the generic algorithm described above.

New in version 2.1.

Changed in version 2.3:Older versions of Python did not support a tuple as the second argument.

intPyCallable_Check(PyObject *o)¶

Determine if the objecto is callable. Return1 if the object is callableand0 otherwise. This function always succeeds.

PyObject*PyObject_Call(PyObject *callable_object,PyObject *args,PyObject *kw)¶

Return value: New reference.

Call a callable Python objectcallable_object, with arguments given by thetupleargs, and named arguments given by the dictionarykw. If no namedarguments are needed,kw may beNULL.args must not beNULL, use anempty tuple if no arguments are needed. Returns the result of the call onsuccess, orNULL on failure. This is the equivalent of the Python expressionapply(callable_object,args,kw) orcallable_object(*args,**kw).

New in version 2.2.

PyObject*PyObject_CallObject(PyObject *callable_object,PyObject *args)¶

Return value: New reference.

Call a callable Python objectcallable_object, with arguments given by thetupleargs. If no arguments are needed, thenargs may beNULL. Returnsthe result of the call on success, orNULL on failure. This is the equivalentof the Python expressionapply(callable_object,args) orcallable_object(*args).

PyObject*PyObject_CallFunction(PyObject *callable, char *format, ...)¶

Return value: New reference.

Call a callable Python objectcallable, with a variable number of C arguments.The C arguments are described using aPy_BuildValue() style formatstring. The format may beNULL, indicating that no arguments are provided.Returns the result of the call on success, orNULL on failure. This is theequivalent of the Python expressionapply(callable,args) orcallable(*args). Note that if you only passPyObject* args,PyObject_CallFunctionObjArgs() is a faster alternative.

PyObject*PyObject_CallMethod(PyObject *o, char *method, char *format, ...)¶

Return value: New reference.

Call the method namedmethod of objecto with a variable number of Carguments. The C arguments are described by aPy_BuildValue() formatstring that should produce a tuple. The format may beNULL, indicating thatno arguments are provided. Returns the result of the call on success, orNULLon failure. This is the equivalent of the Python expressiono.method(args).Note that if you only passPyObject* args,PyObject_CallMethodObjArgs() is a faster alternative.

PyObject*PyObject_CallFunctionObjArgs(PyObject *callable, ..., NULL)¶

Return value: New reference.

Call a callable Python objectcallable, with a variable number ofPyObject* arguments. The arguments are provided as a variable numberof parameters followed byNULL. Returns the result of the call on success, orNULL on failure.

New in version 2.2.

PyObject*PyObject_CallMethodObjArgs(PyObject *o,PyObject *name, ..., NULL)¶

Return value: New reference.

Calls a method of the objecto, where the name of the method is given as aPython string object inname. It is called with a variable number ofPyObject* arguments. The arguments are provided as a variable numberof parameters followed byNULL. Returns the result of the call on success, orNULL on failure.

New in version 2.2.

longPyObject_Hash(PyObject *o)¶

Compute and return the hash value of an objecto. On failure, return-1.This is the equivalent of the Python expressionhash(o).

longPyObject_HashNotImplemented(PyObject *o)¶

Set aTypeError indicating thattype(o) is not hashable and return-1.This function receives special treatment when stored in atp_hash slot,allowing a type to explicitly indicate to the interpreter that it is nothashable.

New in version 2.6.

intPyObject_IsTrue(PyObject *o)¶

Returns1 if the objecto is considered to be true, and0 otherwise.This is equivalent to the Python expressionnotnoto. On failure, return-1.

intPyObject_Not(PyObject *o)¶

Returns0 if the objecto is considered to be true, and1 otherwise.This is equivalent to the Python expressionnoto. On failure, return-1.

PyObject*PyObject_Type(PyObject *o)¶

Return value: New reference.

Wheno is non-NULL, returns a type object corresponding to the object typeof objecto. On failure, raisesSystemError and returnsNULL. Thisis equivalent to the Python expressiontype(o). This function increments thereference count of the return value. There’s really no reason to use thisfunction instead of the common expressiono->ob_type, which returns apointer of typePyTypeObject*, except when the incremented referencecount is needed.

intPyObject_TypeCheck(PyObject *o,PyTypeObject *type)¶

Return true if the objecto is of typetype or a subtype oftype. Bothparameters must be non-NULL.

New in version 2.2.

Py_ssize_tPyObject_Length(PyObject *o)¶

Py_ssize_tPyObject_Size(PyObject *o)¶

Return the length of objecto. If the objecto provides either the sequenceand mapping protocols, the sequence length is returned. On error,-1 isreturned. This is the equivalent to the Python expressionlen(o).

Changed in version 2.5:These functions returned anint type. This might requirechanges in your code for properly supporting 64-bit systems.

PyObject*PyObject_GetItem(PyObject *o,PyObject *key)¶

Return value: New reference.

Return element ofo corresponding to the objectkey orNULL on failure.This is the equivalent of the Python expressiono[key].

intPyObject_SetItem(PyObject *o,PyObject *key,PyObject *v)¶

Map the objectkey to the valuev. Raise an exception andreturn-1 on failure; return0 on success. This is theequivalent of the Python statemento[key]=v.

intPyObject_DelItem(PyObject *o,PyObject *key)¶

Delete the mapping forkey fromo. Returns-1 on failure. This is theequivalent of the Python statementdelo[key].

intPyObject_AsFileDescriptor(PyObject *o)¶

Derives a file descriptor from a Python object. If the object is an integer orlong integer, its value is returned. If not, the object’sfileno() methodis called if it exists; the method must return an integer or long integer, whichis returned as the file descriptor value. Returns-1 on failure.

PyObject*PyObject_Dir(PyObject *o)¶

Return value: New reference.

This is equivalent to the Python expressiondir(o), returning a (possiblyempty) list of strings appropriate for the object argument, orNULL if therewas an error. If the argument isNULL, this is like the Pythondir(),returning the names of the current locals; in this case, if no execution frameis active thenNULL is returned butPyErr_Occurred() will return false.

PyObject*PyObject_GetIter(PyObject *o)¶

Return value: New reference.

This is equivalent to the Python expressioniter(o). It returns a newiterator for the object argument, or the object itself if the object is alreadyan iterator. RaisesTypeError and returnsNULL if the object cannot beiterated.