Expat C API

pyexpat exposes a C interface for extension modules. Consumers must include the header file :file:`pyexpat.h (which is not included by default by Python.h) and expat.h for Expat.

To use the C API, consider adding the following code in your extension module initilisation function and store the pointer to the C API in the module state:

struct PyExpat_CAPI *capi = NULL;
capi = (struct PyExpat_CAPI *)PyCapsule_Import(PyExpat_CAPSULE_NAME, 0);
if (capi == NULL) {
    goto error;
}
if (!PyExpat_CheckCompatibility(capi)) {
    PyErr_SetString(PyExc_ImportError, "pyexpat version is incompatible");
    goto error;
}

int PyExpat_CheckCompatibility(struct PyExpat_CAPI *api)

Return 1 if api is compatible with the linked Expat library, and 0 otherwise. This function never sets a Python exception.

api must not be NULL.

Added in version 3.15.0a1 (unreleased).

PyExpat_CAPI_MAGIC

The Expat C API magic number.

PyExpat_CAPSULE_NAME

The Expat C API capsule name to import via PyCapsule_Import().

struct PyExpat_CAPI

The Expat C API structure.

char *magic

Set to PyExpat_CAPI_MAGIC.

int size

Set to sizeof(struct PyExpat_CAPI).

int MAJOR_VERSION

int MINOR_VERSION

int MICRO_VERSION

Set to XML_MAJOR_VERSION, XML_MINOR_VERSION, and XML_MICRO_VERSION respectively of the linked Expat library.

The following members expose the C API as provided by Expat. See the official documentation for details (some names may slightly differ but the signature and intent will not).

const XML_LChar *(*ErrorString)(enum XML_Error errno)

enum XML_Error (*GetErrorCode)(XML_Parser parser)

XML_Size (*GetErrorColumnNumber)(XML_Parser parser)

XML_Size (*GetErrorLineNumber)(XML_Parser parser)

enum XML_Status (*Parse)(XML_Parser parser, const char *s, int len, int isFinal)

XML_Parser (*ParserCreate_MM)(const XML_Char *encoding, const XML_Memory_Handling_Suite *memsuite, const XML_Char *sep)

void (*ParserFree)(XML_Parser parser)

void (*SetCharacterDataHandler)(XML_Parser parser, XML_CharacterDataHandler handler)

void (*SetCommentHandler)(XML_Parser parser, XML_CommentHandler handler)

void (*SetDefaultHandlerExpand)(XML_Parser parser, XML_DefaultHandler handler)

void (*SetElementHandler)(XML_Parser parser, XML_StartElementHandler start, XML_EndElementHandler end)

void (*SetNamespaceDeclHandler)(XML_Parser parser, XML_StartNamespaceDeclHandler start, XML_EndNamespaceDeclHandler end)

void (*SetProcessingInstructionHandler)(XML_Parser parser, XML_ProcessingInstructionHandler handler)

void (*SetUnknownEncodingHandler)(XML_Parser parser, XML_UnknownEncodingHandler handler, void *encodingHandlerData)

void (*SetUserData)(XML_Parser parser, void *userData)

void (*SetStartDoctypeDeclHandler)(XML_Parser parser, XML_StartDoctypeDeclHandler start)

Added in version 3.2.

enum XML_Status (*SetEncoding)(XML_Parser parser, const XML_Char *encoding)

Added in version 3.3.

int (*DefaultUnknownEncodingHandler)(void *encodingHandlerData, const XML_Char *name, XML_Encoding *info)

Added in version 3.3.

int (*SetHashSalt)(XML_Parser parser, unsigned long hash_salt)

Might be NULL for Expat versions prior to 2.1.0.

Added in version 3.4.

XML_Bool (*SetReparseDeferralEnabled)(XML_Parser parser, XML_Bool enabled)

Might be NULL for Expat versions prior to 2.6.0.

Added in version 3.8.

XML_Bool (*SetAllocTrackerActivationThreshold)(XML_Parser parser, unsigned long long activationThresholdBytes)

Might be NULL for Expat versions prior to 2.7.2.

Added in version 3.10.

XML_Bool (*SetAllocTrackerMaximumAmplification)(XML_Parser parser, float maxAmplificationFactor)

Might be NULL for Expat versions prior to 2.7.2.

Added in version 3.10.

XML_Bool (*SetBillionLaughsAttackProtectionActivationThreshold)(XML_Parser parser, unsigned long long activationThresholdBytes)

Might be NULL for Expat versions prior to 2.4.0.

Added in version 3.10.

XML_Bool (*SetBillionLaughsAttackProtectionMaximumAmplification)(XML_Parser parser, float maxAmplificationFactor)

Might be NULL for Expat versions prior to 2.4.0.

Added in version 3.10.