API v14 for Handwritten Code

In this section we describe the v14 API, provided by the sip module, that can be used by handwritten code in specification files.

In order to be able to support multiple interpreters and free-threading ABI v14 uses modern Python API calls to create and manage extension modules. In particular this means using multi-phase initialisation and using the module state to store module-specific data. Older ABIs used global variables which made it very difficult, if not impossible, to have a module imported more than once.

As a consequence many API calls now require a pointer to a mutable opaque sipModuleState structure as their first argument. In order to make porting from older APIs easier, this argument is handled automatically and can be ignored when API calls are made directly from handwritten code specified in one of the code directives.

However if you are making API calls from helper functions you have written then you must explicitly pass the pointer to the module state to your helper functions and the pointer must be called sipMS.

API Reference

SIP_ABI_MAJOR_VERSION

This is a C preprocessor symbol that defines the major number of the SIP ABI.

SIP_ABI_MINOR_VERSION

This is a C preprocessor symbol that defines the minor number of the SIP ABI.

SIP_BLOCK_THREADS

This is a C preprocessor macro that will make sure that the current thread has an attached thread state. Python API calls must only be made when a thread state is attached. There must be a corresponding SIP_UNBLOCK_THREADS at the same lexical scope.

SIP_NO_CONVERTORS

This is a flag used by various type convertors that suppresses the use of a type’s %ConvertToTypeCode.

SIP_NOT_NONE

This is a flag used by various type convertors that causes the conversion to fail if the Python object being converted is Py_None.

SIP_NULLPTR

This is a C preprocessor macro that can be used instead of NULL or nullptr. It ensures the correct value is used depending on whether C or C++ is being generated and which language standard the compiler supports.

SIP_OWNS_MEMORY

This is a flag used by various array constructors that species that the array owns the memory that holds the array’s contents.

SIP_PROTECTED_IS_PUBLIC

This is a C preprocessor symbol that is defined automatically by the build system to specify that the generated code is being compiled with protected redefined as public. This allows handwritten code to determine if the generated helper functions for accessing protected C++ functions are available (see %MethodCode).

SIP_READ_ONLY

This is a flag used by various array constructors that species that the array is read-only.

void SIP_RELEASE_GIL(sip_gilstate_t sipGILState)

Note

This is provided to ease the support for multiple versions of the ABI. Code targeting ABI v14 only should use PyThreadState_Release() instead.

This is called from the handwritten code specified with the VirtualErrorHandler in order to release the attached thread state prior to changing the execution path (e.g. by throwing a C++ exception). It should not be called under any other circumstances.

Parameters:

  • sipGILState – an opaque value provided to the handwritten code by SIP.

SIP_UNBLOCK_THREADS

This is a C preprocessor macro that will restore the thread state of the current thread to the state it was prior to the corresponding SIP_BLOCK_THREADS.

SIP_VERSION

This is a C preprocessor symbol that defines the SIP version number represented as a 3 part hexadecimal number (e.g. v6.0.0 is represented as 0x060000).

SIP_VERSION_STR

This is a C preprocessor symbol that defines the SIP version number represented as a string. For development versions it will contain .dev.

sipErrorState sipBadCallableArg(int arg_nr, PyObject *arg)

This is called from %MethodCode to raise a Python exception when an argument to a function, a C++ constructor or method is found to have an unexpected type. This should be used when the %MethodCode does additional type checking of the supplied arguments.

Parameters:

  • arg_nr – the number of the argument. Arguments are numbered from 0 but are numbered from 1 in the detail of the exception.

  • arg – the argument.

Returns:

the value that should be assigned to sipError.

void sipBadCatcherResult(PyObject *method)

This raises a Python exception when the result of a Python reimplementation of a C++ method doesn’t have the expected type. It is normally called by handwritten code specified with the %VirtualCatcherCode directive.

Parameters:

  • method – the Python method and would normally be the supplied sipMethod.

void sipBadLengthForSlice(Py_ssize_t seqlen, Py_ssize_t slicelen)

This raises a Python exception when the length of a slice object is inappropriate for a sequence-like object. It is normally called by handwritten code specified for __setitem__() methods.

Parameters:

  • seqlen – the length of the sequence.

  • slicelen – the length of the slice.

PyObject *sipBuildResult(int *is_err_p, const char *format, ...)

This creates a Python object based on a format string and associated values in a similar way to the Python Py_BuildValue() function.

Parameters:

  • is_err_p – if this is not NULL then the location it points to is set to a non-zero value.

  • format – the string of format characters.

Returns:

If there was an error then NULL is returned and a Python exception is raised.

If the format string begins and ends with parentheses then a tuple of objects is created. If it contains more than one format character then parentheses must be specified.

In the following description the first letter is the format character, the entry in parentheses is the Python object type that the format character will create, and the entry in brackets are the types of the C/C++ values to be passed.

a (string) [char]

Convert a C/C++ char to a Python str object.

b (boolean) [bool]

Convert a C/C++ bool to a Python boolean.

c (string/bytes) [char]

Convert a C/C++ char to a Python bytes object.

d (float) [double]

Convert a C/C++ double to a Python floating point number.

e (integer) [enum]

Convert an anonymous C/C++ enum to a Python integer.

f (float) [float]

Convert a C/C++ float to a Python floating point number.

g (string/bytes) [char *, Py_ssize_t]

Convert a C/C++ character array and its length to a Python bytes object. If the array is NULL then the length is ignored and the result is Py_None.

h (integer) [short]

Convert a C/C++ short to a Python integer.

i (integer) [int]

Convert a C/C++ int to a Python integer.

l (long) [long]

Convert a C/C++ long to a Python integer.

m (long) [unsigned long]

Convert a C/C++ unsigned long to a Python long.

n (long) [long long]

Convert a C/C++ long long to a Python long.

o (long) [unsigned long long]

Convert a C/C++ unsigned long long to a Python long.

r (wrapped instance) [type *, Py_ssize_t, sipTypeID]

Convert an array of C structures, C++ classes or mapped type instances to a Python tuple. Note that copies of the array elements are made.

s (string/bytes) [char *]

Convert a C/C++ '\0' terminated string to a Python bytes object. If the string pointer is NULL then the result is Py_None.

t (long) [unsigned short]

Convert a C/C++ unsigned short to a Python long.

u (long) [unsigned int]

Convert a C/C++ unsigned int to a Python long.

w (unicode/string) [wchar_t]

Convert a C/C++ wide character to a Python str object.

x (unicode/string) [wchar_t *]

Convert a C/C++ L'\0' terminated wide character string to a Python str object. If the string pointer is NULL then the result is Py_None.

A (string) [char *]

Convert a C/C++ '\0' terminated string to a Python str object. If the string pointer is NULL then the result is Py_None.

D (wrapped instance) [type *, sipTypeID, PyObject *]

Convert a C structure, C++ class or mapped type instance to a Python object. If the instance has already been wrapped then the result is a new reference to the existing object. Ownership of the instance is determined by the PyObject argument. If it is NULL and the instance has already been wrapped then the ownership is unchanged. If it is NULL and the instance is newly wrapped then ownership will be with C/C++. If it is Py_None then ownership is transferred to Python via a call to sipTransferBack(). Otherwise ownership is transferred to C/C++ and the instance associated with the PyObject argument via a call to sipTransferTo(). The Python class is influenced by any applicable %ConvertToSubClassCode code.

F (wrapped enum) [enum, sipTypeID]

Convert a named C/C++ enum to an instance of the corresponding Python named enum type.

G (unicode) [wchar_t *, Py_ssize_t]

Convert a C/C++ wide character array and its length to a Python unicode object. If the array is NULL then the length is ignored and the result is Py_None.

L (integer) [char]

Convert a C/C++ char to a Python integer.

M (long) [unsigned char]

Convert a C/C++ unsigned char to a Python long.

N (wrapped instance) [type *, sipTypeID, PyObject *]

Convert a new C structure, C++ class or mapped type instance to a Python object. Ownership of the instance is determined by the PyObject argument. If it is NULL and the instance has already been wrapped then the ownership is unchanged. If it is NULL or Py_None then ownership will be with Python. Otherwise ownership will be with C/C++ and the instance associated with the PyObject argument. The Python class is influenced by any applicable %ConvertToSubClassCode code.

R (object) [PyObject *]

The result is value passed without any conversions. The reference count is unaffected, i.e. a reference is taken.

S (object) [PyObject *]

The result is value passed without any conversions. The reference count is incremented.

V (sip.voidptr) [void *]

Convert a C/C++ void * to a Python sip.voidptr object.

z (object) [const char *, void *]

Convert a C/C++ void * to a Python named capsule object.

= (long) [size_t]

Convert a C/C++ size_t to a Python long.

PyObject *sipCallMethod(int *is_err_p, PyObject *method, const char *format, ...)

This calls a Python method passing a tuple of arguments based on a format string and associated values in a similar way to the Python PyObject_CallObject() function.

Parameters:

  • is_err_p – if this is not NULL then the location it points to is set to a non-zero value if there was an error.

  • method – the Python bound method to call.

  • format – the string of format characters (see sipBuildResult()).

Returns:

If there was an error then NULL is returned and a Python exception is raised.

It is normally called by handwritten code specified with the %VirtualCatcherCode directive with method being the supplied sipMethod.

int sipCanConvertToType(PyObject *obj, sipTypeID type_id, int flags)

This checks if a Python object can be converted to an instance of a C structure, C++ class or mapped type.

Parameters:
Returns:

a non-zero value if the object can be converted.

type sipCFunctionDef

This C structure is used with sipGetCFunction() and encapsulates the components parts of a Python C function. The structure elements are as follows.

PyMethodDef *cf_function

The C function.

PyObject *cf_self

The optional bound object.

PyObject *sipConvertFromConstVoidPtr(const void *cpp)

This creates a sip.voidptr object for a memory address. The object will not be writeable and has no associated size.

Parameters:

  • cpp – the memory address.

Returns:

the sip.voidptr object.

PyObject *sipConvertFromConstVoidPtrAndSize(const void *cpp, Py_ssize_t size)

This creates a sip.voidptr object for a memory address. The object will not be writeable and can be used as an immutable buffer object.

Parameters:

  • cpp – the memory address.

  • size – the size associated with the address.

Returns:

the sip.voidptr object.

PyObject *sipConvertFromEnum(void *eval_p, sipTypeID type_id)

This converts a named C/C++ enum to a Python object.

Parameters:
Returns:

the Python object.

PyObject *sipConvertFromNewPyType(void *cpp, PyTypeObject *py_type, sipWrapper *owner, sipSimpleWrapper **self_p, const char *format, ...)

This converts a new C structure or a C++ class instance to an instance of a corresponding Python type (as opposed to the corresponding generated Python type). This is useful when the C/C++ library provides some sort of mechanism whereby handwritten code has some control over the exact type of structure or class being created. Typically it would be used to create an instance of the generated derived class which would then allow Python re-implementations of C++ virtual methods to function properly.

Parameters:

  • cpp – the C/C++ instance.

  • py_type – the Python type object. This is called to create the Python object and is passed the arguments defined by the string of format characters.

  • owner – is the optional owner of the Python object.

  • self_p – is an optional pointer to the sipPySelf instance variable of the C/C++ instance if that instance’s type is a generated derived class. Otherwise it should be NULL.

  • format – the string of format characters (see sipBuildResult()).

Returns:

the Python object. If there was an error then NULL is returned and a Python exception is raised.

PyObject *sipConvertFromNewType(void *cpp, sipTypeID type_id, PyObject *transferObj)

This converts a new C structure or a C++ class instance to an instance of the corresponding generated Python type. Note that care should be taken to ensure that the instance really is new.

Parameters:

  • cpp – the C/C++ instance.

  • type_id – the C/C++ type’s generated type specification.

  • transferObj – this controls the ownership of the returned value.

Returns:

the Python object.

If transferObj is NULL or Py_None then ownership will be with Python.

Otherwise ownership will be with C/C++ and the instance associated with transferObj.

The Python type is influenced by any applicable %ConvertToSubClassCode code.

Py_ssize_t sipConvertFromSequenceIndex(Py_ssize_t idx, Py_ssize_t len)

This converts a Python sequence index (i.e. where a negative value refers to the offset from the end of the sequence) to a C/C++ array index. If the index was out of range then a negative value is returned and a Python exception raised.

Parameters:

  • idx – the sequence index.

  • len – the length of the sequence.

Returns:

the unsigned array index.

int sipConvertFromSliceObject(PyObject *slice, Py_ssize_t length, Py_ssize_t *start, Py_ssize_t *stop, Py_ssize_t *step, Py_ssize_t *slicelength)

This is a thin wrapper around Python’s PySlice_Unpack() and PySlice_AdjustIndices() functions.

PyObject *sipConvertFromType(void *cpp, sipTypeID type_id, PyObject *transferObj)

This converts a C structure or a C++ class instance to an instance of the corresponding generated Python type.

Parameters:

  • cpp – the C/C++ instance.

  • type_id – the C/C++ type’s generated type specification.

  • transferObj – this controls the ownership of the returned value.

Returns:

the Python object.

If the C/C++ instance has already been wrapped then the result is a new reference to the existing object.

If transferObj is NULL and the instance has already been wrapped then the ownership is unchanged.

If transferObj is NULL and the instance is newly wrapped then ownership will be with C/C++.

If transferObj is Py_None then ownership is transferred to Python via a call to sipTransferBack().

Otherwise ownership is transferred to C/C++ and the instance associated with transferObj via a call to sipTransferTo().

The Python class is influenced by any applicable %ConvertToSubClassCode code.

PyObject *sipConvertFromVoidPtr(void *addr)

This creates a sip.voidptr object for a memory address. The object will be writeable but has no associated size.

Parameters:

  • addr – the memory address.

Returns:

the sip.voidptr object.

PyObject *sipConvertFromVoidPtrAndSize(void *addr, Py_ssize_t size)

This creates a sip.voidptr object for a memory address. The object will be writeable and can be used as a mutable buffer object.

Parameters:

  • addr – the memory address.

  • size – the size associated with the address.

Returns:

the sip.voidptr object.

PyObject *sipConvertToArray(void *data, const char *format, Py_ssize_t len, int flags)

This converts a one dimensional array of fundamental types to a sip.array object.

An array is very like a Python memoryview object. The underlying memory is not copied and may be modified in situ. Arrays support the buffer protocol and so can be passed to other modules, again without the underlying memory being copied.

Parameters:

  • data – the address of the start of the C/C++ array.

  • format – the format, as defined by the struct module, of an array element. At the moment only b (char), B (unsigned char), h (short), H (unsigned short), i (int), I (unsigned int), f (float) and d (double) are supported.

  • len – the number of elements in the array.

  • readonly – is non-zero if the array is read-only.

  • flags – any combination of the SIP_READ_ONLY and SIP_OWNS_MEMORY flags.

Returns:

the sip.array object.

bool sipConvertToBool(PyObject *obj)

This converts a Python object to a C++ bool.

Parameters:

  • obj – the Python object to convert.

Returns:

the boolean value. An exception will have been raised (to be tested by calling PyErr_Occurred()) if the conversion failed.

int sipConvertToEnum(PyObject *obj, void *eval_p, sipTypeID type_id)

This converts a Python object to the value of a named C/C++ enum member.

Parameters:

  • obj – the Python object to convert.

  • eval_p – a pointer to the location where the converted enumerated value is returned.

  • type_id – the enum’s generated type specification.

Returns:

-1 is returned, and a Python exception raised, if there was an error. Otherwise 0 is returned.

void *sipConvertToType(PyObject *obj, sipTypeID type_id, PyObject *transferObj, int flags, int *state_p, int *is_err_p)

This converts a Python object to an instance of a C structure, C++ class or mapped type similar to sipConvertToTypeUS() but without support for any user state.

Parameters:

  • obj – the Python object.

  • type_id – the C/C++ type’s generated type specification.

  • transferObj – this controls any ownership changes to obj.

  • flags – any combination of the SIP_NOT_NONE and SIP_NO_CONVERTORS flags.

  • state_p – the state of the returned C/C++ instance is returned via this pointer.

  • is_err_p – the error flag is passed and updated via this pointer.

Returns:

the C/C++ instance.

See sipConvertToTypeUS() for a full description of the arguments.

void *sipConvertToTypeUS(PyObject *obj, sipTypeID type_id, PyObject *transferObj, int flags, int *state_p, void **user_state_p, int *is_err_p)

This converts a Python object to an instance of a C structure, C++ class or mapped type assuming that a previous call to sipCanConvertToType() has been successful.

Parameters:

  • obj – the Python object.

  • type_id – the C/C++ type’s generated type specification.

  • transferObj – this controls any ownership changes to obj.

  • flags – any combination of the SIP_NOT_NONE and SIP_NO_CONVERTORS flags.

  • state_p – the state of the returned C/C++ instance is returned via this pointer.

  • user_state_p – any additional state of the returned C/C++ instance is returned via this pointer.

  • is_err_p – the error flag is passed and updated via this pointer.

Returns:

the C/C++ instance.

If transferObj is NULL then the ownership is unchanged. If it is Py_None then ownership is transferred to Python via a call to sipTransferBack().

Otherwise ownership is transferred to C/C++ and obj associated with transferObj via a call to sipTransferTo().

Note that obj can also be managed by the C/C++ instance itself, but this can only be achieved by using sipTransferTo().

If state_p is not NULL then the location it points to is set to describe the state of the returned C/C++ instance and is the value returned by any %ConvertToTypeCode. The calling code must then release the value at some point to prevent a memory leak by calling sipReleaseType().

If user_state_p is not NULL then the location it points to may be used by the type convertor for any purpose, typically to store a pointer to additional state on the heap. Any such pointer is passed to the type’s corresponding sipReleaseTypeUS() function.

If there is an error then the location is_err_p points to is set to a non-zero value. If it was initially a non-zero value then the conversion isn’t attempted in the first place. (This allows several calls to be made that share the same error flag so that it only needs to be tested once rather than after each call.)

PyObject *sipConvertToTypedArray(void *data, sipTypeID type_id, const char *format, size_t stride, Py_ssize_t len, int flags)

This converts a one dimensional array of instances of a C structure, C++ class or mapped type to a sip.array object.

An array is very like a Python memoryview object but it’s elements correspond to C structures or C++ classes. The underlying memory is not copied and may be modified in situ. Arrays support the buffer protocol and so can be passed to other modules, again without the underlying memory being copied.

Parameters:

  • data – the address of the start of the C/C++ array.

  • type_id – an element’s type’s generated type specification.

  • format – the format, as defined by the struct module, of an array element.

  • stride – the size of an array element, including any padding.

  • len – the number of elements in the array.

  • flags – the optional SIP_READ_ONLY flag.

Returns:

the sip.array object.

void *sipConvertToVoidPtr(PyObject *obj)

This converts a Python object to a memory address. PyErr_Occurred() must be used to determine if the conversion was successful.

Parameters:

  • obj – the Python object which may be Py_None, a sip.voidptr or a PyCObject.

Returns:

the memory address.

type sipDateDef

This C structure is used with sipGetDate(), sipFromDate(), sipGetDateTime() and sipFromDateTime() and encapsulates the components parts of a Python date. The structure elements are as follows.

int pd_year

The year.

int pd_month

The month (1-12).

int pd_day

The day (1-31).

int sipEnableAutoconversion(PyTypeObject *py_type, int enable)

Instances of some classes may be automatically converted to other Python objects even though the class has been wrapped. This allows that behaviour to be suppressed so that an instances of the wrapped class is returned instead.

Parameters:

  • py_type – the type object of the type. This must refer to a wrapped class.

  • enable – is non-zero if auto-conversion should be enabled for the type. This is the default behaviour.

Returns:

1 or 0 depending on whether or not auto-conversion was previously enabled for the type. This allows the previous state to be restored later on. -1 is returned, and a Python exception raised, if there was an error.

int sipEnableGC(int enable)

This enables or disables the Python garbarge collector.

Parameters:

  • enable – is greater than 0 if the garbage collector should be enabled.

Returns:

1 or 0 depending on whether or not the garbage collector was previously enabled. This allows the previous state to be restored later on. -1 is returned if there was an error.

enum sipErrorState

This enum defines the different error states when parsing function signatures.

enumerator sipErrorNone

There is no error.

enumerator sipErrorFail

There was an error and signature parsing should stop.

enumerator sipErrorContinue

There was an error but signature parsing should continue.

type sipEventHandlerSpec

An array of this C structure is used with sipRegisterEventHandlers() to define a set of event handlers registered by a module. The structure elements are as follows.

sipEventType event_type

The event type. sipEventNone is used to denote the end of the the array.

sipTypeID type_id

The type specification of the type the handler handles.

void *handler

The handler function.

enum sipEventType

This enum defines the different event types. Event handlers may be registered using sipRegisterEventHandlers().

enumerator sipEventCollectingModule

This event is triggered whenever a wrapped module is being garbage collected. The handler is not passed any arguments.

enumerator sipEventCollectingWrapper

This event is triggered whenever a Python wrapper object is being garbage collected. The handler is passed a pointer to the opaque module state, the type’s type identifier and a pointer to the sipSimpleWrapper being garbage collected.

enumerator sipEventFinalisingAddress

This event is triggered before a C/C++ instance is wrapped as a Python object to allow the bindings to replace it with another instance (e.g. a proxy). The handler is passed a pointer to the opaque module state, the type’s type identifier and a void * which is the address of the C/C++ instance. The handler should return the void * address to be used by the wrapper. The handler should raise a Python exception and return NULL if there was an error.

enumerator sipEventFinalisingType

This event is triggered when a new wrapped type has been created to allow additional changes to be made to the type. The handler is passed a pointer to the opaque module state, the type’s type identifier and a pointer to a PyTypeObject which is the new type object. The handler should raise a Python exception and return -1 if there was an error, otherwise 0 should be returned.

enumerator sipEventNone

This is used as a sentinal marking the last entry in an array of sipEventHandlerSpec.

enumerator sipEventWrappedInstance

This event is triggered whenever a C/C++ instance that is created by C/C++ (and not by Python) is wrapped. The handler is passed a pointer to the opaque module state, the type’s type identifier and a void * which is the address of the C/C++ instance.

void sipExportSymbols(const sipSymbolSpec *const symbols)

Python does not allow extension modules to directly access symbols in another extension module. This exports a number of symbols, each referenced by a name, that can subsequently be imported, using sipImportSymbol(), by another module.

Parameters:

  • symbols – the array of sipSymbolSpec specifications of symbol names and their corresponding values.

sipTypeID sipFindType(const char *type)

This returns the type identifier of a C/C++ type.

Parameters:

  • type – the C/C++ declaration of the type.

Returns:

the type identifier. sipType_Invalid is returned if the C/C++ type doesn’t exist.

void *sipForceConvertToType(PyObject *obj, sipTypeID type_id, PyObject *transferObj, int flags, int *state, int *iserr)

This converts a Python object to an instance of a C structure, C++ class or mapped type similar to sipForceConvertToTypeUS() but without support for any user state.

See sipForceConvertToType() for a full description of the arguments.

void *sipForceConvertToTypeUS(PyObject *obj, sipTypeID type_id, PyObject *transferObj, int flags, int *state, void **user_state, int *iserr)

This converts a Python object to an instance of a C structure, C++ class or mapped type by calling sipCanConvertToType() and, if it is successfull, calling sipConvertToTypeUS().

See sipConvertToTypeUS() for a full description of the arguments.

void sipFree(void *mem)

This returns an area of memory allocated by sipMalloc() to the heap.

Parameters:

  • mem – the memory address.

PyObject *sipFromDate(const sipDateDef *date)

This creates a Python date object from its component parts.

Parameters:

  • date – the component parts of the date.

Returns:

the Python date object.

PyObject *sipFromDateTime(const sipDateDef *date, const sipTimeDef *time)

This creates a Python datetime object from its component parts.

Parameters:

  • date – the date related component parts of the datetime.

  • time – the time related component parts of the datetime.

Returns:

the Python datetime object.

PyObject *sipFromMethod(const sipMethodDef *method)

This creates a Python method object from its component parts.

Parameters:

  • method – the component parts of the method.

Returns:

the Python method object.

PyObject *sipFromTime(const sipTimeDef *time)

This creates a Python time object from its component parts.

Parameters:

  • time – the component parts of the time.

Returns:

the Python time object.

void *sipGetAddress(sipSimpleWrapper *obj)

This returns the address of the C structure or C++ class instance wrapped by a Python object.

Parameters:

  • obj – the Python object.

Returns:

the address of the C/C++ instance.

int sipGetCFunction(PyObject *obj, sipCFunctionDef *c_function)

This checks to see if an object is a Python C function object and, if so, optionally returns its component parts.

Parameters:

  • obj – the Python object.

  • c_function – if this is not NULL, and the object is a C function object, then the component parts are returned in this structure.

Returns:

a non-zero value if the object is a Python C function object.

int sipGetDate(PyObject *obj, sipDateDef *date)

This checks to see if an object is a Python date object and, if so, optionally returns its component parts.

Parameters:

  • obj – the Python object.

  • date – if this is not NULL, and the object is a date object, then the component parts are returned in this structure.

Returns:

1 if the object is a Python date object, 0 if not and -1 if there was an error.

int sipGetDateTime(PyObject *obj, sipDateDef *date, sipTimeDef *time)

This checks to see if an object is a Python datetime object and, if so, optionally returns its component parts.

Parameters:

  • obj – the Python object.

  • date – if this is not NULL, and the object is a datetime object, then the date related component parts are returned in this structure.

  • time – if this is not NULL, and the object is a datetime object, then the time related component parts are returned in this structure.

Returns:

1 if the object is a Python datetime object, 0 if not and -1 if there was an error.

PyFrameObject *sipGetFrameRef(int depth)

This retrieves a new reference to a frame object from the current execution stack.

Note

On PyPy this will always return NULL.

Parameters:

  • depth – the depth of frame to retrieve where 0 is the current frame, 1 is the previous frame etc.

Returns:

the opaque frame or NULL if there wasn’t one at the given depth.

PyInterpreterView *sipGetInterpreterView()

This returns the current interpreter view. Call PyInterpreterGuard_FromView() to determine if the interpreter is usable.

Returns:

the current interpreter view.

int sipGetMethod(PyObject *obj, sipMethodDef *method)

This checks to see if an object is a Python method object and, if so, optionally returns its component parts.

Parameters:

  • obj – the Python object.

  • method – if this is not NULL, and the object is a method object, then the component parts are returned in this structure.

Returns:

a non-zero value if the object is a Python method object.

void *sipGetModuleUserState()

This returns the address of the user supplied module state structure set by sipSetModuleUserState().

Returns:

the address of the state structure.

PyObject *sipGetPyObjectRef(void *cppptr, sipTypeID type_id)

This returns a new reference to the Python object for a C structure or C++ class instance.

Parameters:
Returns:

the Python object or NULL (and no exception is raised) if the C/C++ instance hasn’t been wrapped.

PyTypeObject *sipGetPyTypeRef(sipTypeID type_id)

This returns a new reference to the Python type object that SIP creates for a wrapped type.

Parameters:
Returns:

the Python type object. If the type structure refers to a mapped type then NULL will be returned.

PyTypeObject *sipGetSimpleWrapperType()

This returns the type of the PyObject structure used to wrap simple types (i.e. those that do not support parent/child relationships). It is exposed to Python code as sip.simplewrapper.

Returns:

a borrowed reference to the type object.

int sipGetState(PyObject *transferObj)

The %ConvertToTypeCode directive requires that the provided code returns an int describing the state of the converted value. The state usually depends on any transfers of ownership that have been requested. This is a convenience function that returns the correct state when the converted value is a temporary.

Parameters:

  • transferObj – the object that describes the requested transfer of ownership.

Returns:

the state of the converted value.

int sipGetTime(PyObject *obj, sipTimeDef *time)

This checks to see if an object is a Python time object and, if so, optionally returns its component parts.

Parameters:

  • obj – the Python object.

  • time – if this is not NULL, and the object is a time object, then the component parts are returned in this structure.

Returns:

1 if the object is a Python time object, 0 if not and -1 if there was an error.

PyObject *sipGetTypeUserObject(sipWrapperType *type)

Each generated type corresponding to a wrapped C/C++ type, or a user sub-class of such a type, contains an optional reference to a Python object that can be used for any purpose by handwritten code and will automatically be garbage collected at the appropriate time. This returns a reference to that object.

Parameters:

  • type – the wrapped type object.

Returns:

a new reference to the type-specific user object.

PyObject *sipGetUserObject(sipSimpleWrapper *obj)

Each wrapped instance contains an optional reference to a Python object that can be used for any purpose by handwritten code and will automatically be garbage collected at the appropriate time. This returns a reference to that object.

Parameters:

  • obj – the wrapped instance.

Returns:

a new reference to the instance-specific user object.

PyTypeObject *sipGetVoidPtrType()

This returns the type of the PyObject structure that is used to wrap a void *. It is exposed to Python code as sip.voidptr.

Returns:

a borrowed reference to the type object.

PyTypeObject *sipGetWrapperType()

This returns the type of the PyObject structure used to wrap types. It is exposed to Python code as sip.wrapper.

Returns:

a borrowed reference to the type object.

PyTypeObject *sipGetWrapperTypeType()

This returns the metatype of the PyObject structure used to wrap types (both simple and non-simple). It is exposed to Python code as sip.wrappertype.

Returns:

a borrowed reference to the type object.

void *sipImportSymbol(const char *name)

Python does not allow extension modules to directly access symbols in another extension module. This imports a symbol, referenced by a name, that has previously been exported, using sipExportSymbols(), by another module.

Parameters:

  • name – the name of the symbol.

Returns:

the value of the symbol. NULL is returned (but no exception set) if there is no such symbol.

void sipInstanceDestroyed(sipSimpleWrapper **obj_p)

This should be called by handwritten code if it is able to detect that a wrapped C++ instance has been destroyed from C++. It should not be called if SIP is able to detect this itself, i.e. when the instance was created from Python and the class has a virtual destructor.

Parameters:

  • obj_p – a pointer to the Python object that wraps the destroyed instance. It will be set to NULL when the call returns.

int sipIsEnumFlag(PyObject *obj)

This determines if an object is a sub-class of enum.Flag.

Parameters:

  • obj – the object.

Returns:

a non-zero value if the object is a enum.Flag sub-class.

int sipIsOwnedByPython(sipSimpleWrapper *obj)

This determines if a wrapped object is currently owned by Python.

Parameters:

  • obj – the wrapped object.

Returns:

a non-zero value if the object is currently owned by Python.

int sipIsUserType(const sipWrapperType *type)

This checks if a type corresponds to a wrapped C/C++ type or a user sub-class of such a type.

Parameters:

  • type – the type object.

Returns:

a non-zero value if the type is a user defined type.

char sipLong_AsChar(PyObject *obj)

This converts a Python object to a C/C++ char. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

signed char sipLong_AsSignedChar(PyObject *obj)

This converts a Python object to a C/C++ signed char. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

unsigned char sipLong_AsUnsignedChar(PyObject *obj)

This converts a Python object to a C/C++ unsigned char. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

short sipLong_AsShort(PyObject *obj)

This converts a Python object to a C/C++ short. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

unsigned short sipLong_AsUnsignedShort(PyObject *obj)

This converts a Python object to a C/C++ unsigned short. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

int sipLong_AsInt(PyObject *obj)

This converts a Python object to a C/C++ int. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

unsigned int sipLong_AsUnsignedInt(PyObject *obj)

This converts a Python object to a C/C++ unsigned int. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

size_t sipLong_AsSizeT(PyObject *obj)

This converts a Python object to a C/C++ size_t. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

long sipLong_AsLong(PyObject *obj)

This converts a Python object to a C/C++ long. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

unsigned long sipLong_AsUnsignedLong(PyObject *obj)

This converts a Python object to a C/C++ unsigned long. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

long long sipLong_AsLongLong(PyObject *obj)

This converts a Python object to a C/C++ long long. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

unsigned long long sipLong_AsUnsignedLongLong(PyObject *obj)

This converts a Python object to a C/C++ unsigned long long. If the value is too large then an exception is raised.

Parameters:

  • obj – the Python object.

Returns:

the converted C/C++ value.

void *sipMalloc(size_t nbytes)

This allocates an area of memory on the heap using the Python PyMem_RawMalloc() function. The memory is freed by calling sipFree().

Parameters:

  • nbytes – the number of bytes to allocate.

Returns:

the memory address. If there was an error then NULL is returned and a Python exception raised.

type sipMethodDef

This C structure is used with sipGetMethod() and sipFromMethod() and encapsulates the components parts of a Python method. The structure elements are as follows.

PyObject *pm_function

The function that implements the method.

PyObject *pm_self

The bound object.

type sipModuleState

This mutable opaque C structure is the state data of a generated extension module. A pointer to this (called sipMS) is made available to all handwritten code and should be passed to any helper functions that make API calls themselves.

void sipObjectDump(PyObject *obj)

This is a thin wrapper around PyObject_Dump() that is typically used when debugging when the limited Python API is enabled.

Parameters:

  • obj – the Python object.

int sipParseResult(PyThreadStateToken *tst, const char *error_handler, PyObject *self, PyObject *method, PyObject *result, const char *format, ...)

This converts a Python object (usually returned by a method) to C/C++ based on a format string and associated values in a similar way to the Python PyArg_ParseTuple() function.

Parameters:

  • tst – the thread state token.

  • error_handler – the name of the error handler.

  • self – the Python self object.

  • method – the Python method that returned result.

  • result – the Python object returned by method.

  • format – the format string.

Returns:

0 if there was no error. Otherwise a negative value is returned, and an exception raised.

This is normally called by handwritten code specified with the %VirtualCatcherCode directive with tst being the supplied sipTST, error_handler being the the supplied sipErrorHandler, self being the supplied sipPySelf, method being the supplied sipMethod and result being the value returned by sipCallMethod().

If format begins and ends with parentheses then result must be a Python tuple and the rest of format is applied to the tuple contents.

In the following description the first letter is the format character, the entry in parentheses is the Python object type that the format character will convert, and the entry in brackets are the types of the C/C++ values to be passed.

ae (object) [char *]

Convert a Python string-like object of length 1 to a C/C++ char according to the encoding e. e can either be A for ASCII, L for Latin-1, or 8 for UTF-8. The object may either be a bytes object or a str object that can be encoded. An object that supports the buffer protocol may also be used.

b (integer) [bool *]

Convert a Python bool or integer to a C/C++ bool.

c (bytes) [char *]

Convert a Python bytes object of length 1 to a C/C++ char.

d (float) [double *]

Convert a Python floating point number to a C/C++ double.

e (integer) [enum *]

Convert a Python integer to an anonymous C/C++ enum.

f (float) [float *]

Convert a Python floating point number to a C/C++ float.

g (bytes) [const char **, Py_ssize_t *]

Convert a Python bytes object to a C/C++ character array and its length. If the Python object is Py_None then the array and length are NULL and zero respectively.

h (integer) [short *]

Convert a Python integer to a C/C++ short.

i (integer) [int *]

Convert a Python integer to a C/C++ int.

l (long) [long *]

Convert a Python long to a C/C++ long.

m (long) [unsigned long *]

Convert a Python long to a C/C++ unsigned long.

n (long) [long long *]

Convert a Python long to a C/C++ long long.

o (long) [unsigned long long *]

Convert a Python long to a C/C++ unsigned long long.

t (long) [unsigned short *]

Convert a Python long to a C/C++ unsigned short.

u (long) [unsigned int *]

Convert a Python long to a C/C++ unsigned int.

w (string) [wchar_t *]

Convert a Python str object of length 1 to a C/C++ wide character.

x (string) [wchar_t **]

Convert a Python str object to a C/C++ L'\0' terminated wide character string. If the Python object is Py_None then the string is NULL.

Ae (object) [int, const char **]

Convert a Python string-like object to a C/C++ '\0' terminated string according to the encoding e. e can either be A for ASCII, L for Latin-1, or 8 for UTF-8. If the Python object is Py_None then the string is NULL. The integer uniquely identifies the object in the context defined by the S format character and allows an extra reference to the object to be kept to ensure that the string remains valid. The object may either be a bytes object or a str object that can be encoded. An object that supports the buffer protocol may also be used.

B (bytes) [int, const char **]

Convert a Python bytes object to a C/C++ '\0' terminated string. If the Python object is Py_None then the string is NULL. The integer uniquely identifies the object in the context defined by the S format character and allows an extra reference to the object to be kept to ensure that the string remains valid.

F (wrapped enum) [sipTypeDef *, enum *]

Convert a Python named enum type to the corresponding C/C++ enum.

G (string) [wchar_t **, Py_ssize_t *]

Convert a Python str object to a C/C++ wide character array and its length. If the Python object is Py_None then the array and length are NULL and zero respectively.

Hf (wrapped instance) [const sipTypeDef *, int *, void **]

Convert a Python object to a C structure, C++ class or mapped type instance as described in sipConvertToType(). f is a combination of the following flags encoded as an ASCII character by adding 0 to the combined value:

0x01 disallows the conversion of Py_None to NULL

0x02 implements the Factory and TransferBack annotations

0x04 returns a copy of the C/C++ instance.

L (integer) [signed char *]

Convert a Python integer to a C/C++ signed char.

M (long) [unsigned char *]

Convert a Python long to a C/C++ unsigned char.

N (object) [PyTypeObject *, PyObject **]

A Python object is checked to see if it is a certain type and then returned without any conversions. The reference count is incremented. The Python object may be Py_None.

O (object) [PyObject **]

A Python object is returned without any conversions. The reference count is incremented.

T (object) [PyTypeObject *, PyObject **]

A Python object is checked to see if it is a certain type and then returned without any conversions. The reference count is incremented. The Python object may not be Py_None.

V (sip.voidptr) [void **]

Convert a Python sip.voidptr object to a C/C++ void *.

z (object) [const char *, void **]

Convert a Python named capsule object to a C/C++ void *.

Z (object) []

Check that a Python object is Py_None. No value is returned.

! (object) [PyObject **]

A Python object is checked to see if it implements the buffer protocol and then returned without any conversions. The reference count is incremented. The Python object may not be Py_None.

$ (object) [PyObject **]

A Python object is checked to see if it implements the buffer protocol and then returned without any conversions. The reference count is incremented. The Python object may be Py_None.

= (long) [size_t *]

Convert a Python long to a C/C++ size_t.

PyObject *sipPyTypeDictRef(PyTypeObject *py_type)

This is a thin wrapper around PyType_GetDict() and is typically used when the limited Python API is enabled.

Parameters:

  • py_type – the type object.

Returns:

a new reference to type object’s read-only type dictionary.

int sipRegisterEventHandlers(const sipEventHandlerSpec *const handler_specs)

This registers a number of event handlers which will be called whenever the corresponding event is triggered.

Parameters:

  • handler_specs – the array of sipEventHandlerSpec specifications of event types are their corresponding handlers.

Returns:

0 if there was no error, otherwise -1 is returned (and a Python exception is raised).

int sipRegisterPyType(PyTypeObject *type)

This registers a Python type object that can be used as the meta-type or super-type of a wrapped C++ type.

Parameters:

  • type – the type object.

Returns:

0 if there was no error, otherwise -1 is returned.

See the section Types and Meta-types for more details.

void sipReleaseType(void *cpp, sipTypeID type_id, int state)

This releases a wrapped C/C++ or mapped type instance to the heap if it was a temporary instance similar to sipReleaseTypeUS() but without support for any user state.

Parameters:

  • cpp – the C/C++ instance.

  • type_id – the C/C++ type’s generated type specification.

  • state – describes the state of the C/C++ instance.

See sipReleaseTypeUS() for a full description of the arguments.

void sipReleaseTypeUS(void *cpp, sipTypeID type_id, int state, void *user_state)

This releases a wrapped C/C++ or mapped type instance to the heap if it was a temporary instance. It is called after a call to either sipConvertToTypeUS() or sipForceConvertToTypeUS().

Parameters:
const char *sipResolveTypedef(const char *name)

This returns the value of a C/C++ typedef.

Parameters:

  • name – the name of the typedef.

Returns:

the value of the typedef. If there was no such typedef then name will be returned.

void sipSetModuleUserState(void *user_state, sipModuleUserStateClearFunc clear, sipModuleUserStateFreeFunc free, sipModuleUserStateTraverseFunc traverse)

This sets the address of the user supplied module state structure. It can be obtained by calling sipGetModuleUserState(). It also sets a number of functions that are called to manage the lifecycle of the structure.

This structure is defined and used by bindings authors to avoid using static variables in their handwritten code so that multiple interpreters can be supported. This function is normally called from %InitialisationCode.

Parameters:

  • user_state – the address of the state structure.

  • clear – the optional function that is called by the module’s clear slot. It is passed a pointer to the opaque module state and the address of the state structure. It should return an int that is normally 0 or -1 to indicate an error.

  • free – the optional function that is called by the module’s free slot. It is passed a pointer to the opaque module state and the address of the state structure.

  • traverse – the optional function that is called by the module’s traverse slot. It is passed a pointer to the opaque module state, the address of the state structure and the visitproc and arg arguments that were passed to the module’s traverse slot. It should return an int that is normally 0 or the result returned by any calls to visitproc. This function must only call the DuringGC Python functions.

void sipSetTypeUserObject(sipWrapperType *type, PyObject *user)

Each generated type corresponding to a wrapped C/C++ type, or a user sub-class of such a type, can contain a reference to a single Python object that can be used for any purpose by handwritten code and will automatically be garbage collected at the appropriate time. This sets that object.

Parameters:

  • type – the type object.

  • user – the type-specific user object.

void sipSetUserObject(sipSimpleWrapper *obj, PyObject *user)

Each wrapped object can contain a reference to a single Python object that can be used for any purpose by handwritten code and will automatically be garbage collected at the appropriate time. This sets that object.

Parameters:

  • obj – the wrapped object.

  • user – the instance-specific user object.

type sipSimpleWrapper

This is an opaque C structure that implements a Python wrapped instance whose type is sip.simplewrapper. It is an extension of the PyObject structure and so may be safely cast to it.

type sipSymbolSpec

An array of this C structure is used with sipExportSymbols() to define a set of symbols exported by a module. The structure elements are as follows.

const char *name

The name of the symbol. NULL is used to denote the end of the array.

void *symbol

The value of the symbol.

type sipTimeDef

This C structure is used with sipGetTime(), sipFromTime(), sipGetDateTime() and sipFromDateTime() and encapsulates the components parts of a Python time. The structure elements are as follows.

int pt_hour

The hour (0-23).

int pt_minute

The minute (0-59).

int pt_second

The second (0-59).

int pt_microsecond

The microsecond (0-999999).

void sipTransferBack(PyObject *obj)

This transfers ownership of a Python wrapped instance to Python (see Ownership of Objects).

Parameters:

  • obj – the wrapped instance.

In addition, any association of the instance with regard to the cyclic garbage collector with another instance is removed.

void sipTransferTo(PyObject *obj, PyObject *owner)

This transfers ownership of a Python wrapped instance to C++ (see Ownership of Objects).

Parameters:

  • obj – the wrapped instance.

  • owner – an optional wrapped instance that obj becomes associated with with regard to the cyclic garbage collector. If owner is NULL then no such association is made. If owner is Py_None then obj is given an extra reference which is removed when the C++ instance’s destructor is called. If owner is the same value as obj then any reference cycles involving obj can never be detected or broken by the cyclic garbage collector. Responsibility for calling the C++ instance’s destructor is always transfered to C++.

type sipTypeID

This opaque C type is the ABI’s representation of a generated type specification.

int sipTypeIsClass(sipTypeID type_id)

This checks if a type specification refers to a C structure or C++ class or namespace.

Parameters:
Returns:

a non-zero value if the type specification refers to a structure, class or namespace.

int sipTypeIsEnum(sipTypeID type_id)

If the CustomEnums option was specified in the SipModuleConfiguration directive then this checks if a type specification refers to a C-style named enum.

If the PyEnums option was specified in the SipModuleConfiguration directive then this checks if a type specification refers to any style of named enum.

Parameters:
Returns:

a non-zero value if the type specification refers to an appropriate enum.

int sipTypeIsMapped(sipTypeID type_id)

This checks if a type specification refers to a mapped type.

Parameters:
Returns:

a non-zero value if the type specification refers to a mapped type.

int sipTypeIsScopedEnum(sipTypeID type_id)

This checks if a type specification refers to a C++11 scoped enum. It is only present if the CustomEnums option was specified in the SipModuleConfiguration directive.

Parameters:
Returns:

a non-zero value if the type specification refers to a C++11 scoped enum.

sipTypeID sipTypeScope(sipTypeID type_id)

This returns the type specification of the enclosing scope of a wrapped type.

Parameters:
Returns:

the type specification of the scope or sipType_Invalid if the type has no scope.

void *sipUnicodeData(PyObject *obj, int *char_size, Py_ssize_t *len)

This returns information about the contents of a Python unicode object.

Parameters:

  • obj – the unicode object.

  • char_size – a pointer which will be updated with the number of bytes (either 1, 2 or 4) used to store a character. If there was an error then this will be a negative value.

  • len – a pointer which will be updated with the number of characters (not bytes) in the unicode object.

Returns:

the address of the buffer where the characters are stored. It will be undefined if the returned character size is a negative value.

PyObject *sipUnicodeNew(Py_ssize_t len, unsigned maxchar, int *kind, void **data)

This creates a Python unicode object that will hold a set number of characters, each character being of a certain size.

Parameters:

  • len – the number of characters.

  • maxchar – the largest code point that will be placed in the object.

  • kind – a pointer which will be updated with a value that represents the number of bytes (either 1, 2 or 4) used to store a character.

  • data – a pointer which will be updated with the address of the buffer where the characters will be stored.

Returns:

the unicode object or NULL if there was an error.

void sipUnicodeWrite(int kind, void *data, int index, unsigned value)

This updates the buffer of a Python unicode object with a character at a particular position.

Parameters:

  • kind – the value that represents the number of bytes (either 1, 2 or 4) used to store a character.

  • data – the address of the buffer where the characters are stored.

  • index – the character (not byte) index of the character to be updated.

  • value – the value of the new character.

void sipVisitWrappers(sipWrapperVisitorFunc visitor, void *closure)

This calls a visitor function for every wrapper object.

Parameters:

  • visitor – the visitor function.

  • closure – a pointer that is passed to the visitor.

A visitor has the following signature.

void visitor(sipSimpleWrapper *obj, void *closure)

obj is the wrapped object being visited.

closure is the pointer passed to sipVisitWrappers().

type sipWrapper

This is an opaque C structure that implements a Python wrapped instance whose type is sip.wrapper. It is an extension of the sipSimpleWrapper and PyObject structures and so may be safely cast to both.

type sipWrapperType

This is an opaque C structure that implements a SIP generated type object. It is an extension of the PyTypeObject structure (which is itself an extension of the PyObject structure) and so may be safely cast to PyTypeObject (and PyObject).

Version History

v14.0

The initial version.