Bytes Objects

These functions raise TypeError when expecting a bytes parameter and are called with a non-bytes parameter.

PyBytesObject

This subtype of PyObject represents a Python bytes object.

PyTypeObject PyBytes_Type

This instance of PyTypeObject represents the Python bytes type; it is the same object as bytes in the Python layer.

int PyBytes_Check(PyObject *o)

Return true if the object o is a bytes object or an instance of a subtype of the bytes type.

int PyBytes_CheckExact(PyObject *o)

Return true if the object o is a bytes object, but not an instance of a subtype of the bytes type.

PyObject* PyBytes_FromString(const char *v)

Return a new bytes object with a copy of the string v as value on success, and NULL on failure. The parameter v must not be NULL; it will not be checked.

PyObject* PyBytes_FromStringAndSize(const char *v, Py_ssize_t len)

Return a new bytes object with a copy of the string v as value and length len on success, and NULL on failure. If v is NULL, the contents of the bytes object are uninitialized.

PyObject* PyBytes_FromFormat(const char *format, ...)

Take a C printf()-style format string and a variable number of arguments, calculate the size of the resulting Python bytes object and return a bytes object with the values formatted into it. The variable arguments must be C types and must correspond exactly to the format characters in the format string. The following format characters are allowed:

Format Characters	Type	Comment
%%	n/a	The literal % character.
%c	int	A single character, represented as an C int.
%d	int	Exactly equivalent to printf("%d").
%u	unsigned int	Exactly equivalent to printf("%u").
%ld	long	Exactly equivalent to printf("%ld").
%lu	unsigned long	Exactly equivalent to printf("%lu").
%zd	Py_ssize_t	Exactly equivalent to printf("%zd").
%zu	size_t	Exactly equivalent to printf("%zu").
%i	int	Exactly equivalent to printf("%i").
%x	int	Exactly equivalent to printf("%x").
%s	char*	A null-terminated C character array.
%p	void*	The hex representation of a C pointer. Mostly equivalent to printf("%p") except that it is guaranteed to start with the literal 0x regardless of what the platform’s printf yields.

An unrecognized format character causes all the rest of the format string to be copied as-is to the result string, and any extra arguments discarded.

PyObject* PyBytes_FromFormatV(const char *format, va_list vargs)

Identical to PyBytes_FromFormat() except that it takes exactly two arguments.

PyObject* PyBytes_FromObject(PyObject *o)

Return the bytes representation of object o that implements the buffer protocol.

Py_ssize_t PyBytes_Size(PyObject *o)

Return the length of the bytes in bytes object o.

Py_ssize_t PyBytes_GET_SIZE(PyObject *o)

Macro form of PyBytes_Size() but without error checking.

char* PyBytes_AsString(PyObject *o)

Return a NUL-terminated representation of the contents of o. The pointer refers to the internal buffer of o, not a copy. The data must not be modified in any way, unless the string was just created using PyBytes_FromStringAndSize(NULL, size). It must not be deallocated. If o is not a string object at all, PyBytes_AsString() returns NULL and raises TypeError.

char* PyBytes_AS_STRING(PyObject *string)

Macro form of PyBytes_AsString() but without error checking.

int PyBytes_AsStringAndSize(PyObject *obj, char **buffer, Py_ssize_t *length)

Return a NUL-terminated representation of the contents of the object obj through the output variables buffer and length.

If length is NULL, the resulting buffer may not contain NUL characters; if it does, the function returns -1 and a TypeError is raised.

The buffer refers to an internal string buffer of obj, not a copy. The data must not be modified in any way, unless the string was just created using PyBytes_FromStringAndSize(NULL, size). It must not be deallocated. If string is not a string object at all, PyBytes_AsStringAndSize() returns -1 and raises TypeError.

void PyBytes_Concat(PyObject **bytes, PyObject *newpart)

Create a new bytes object in *bytes containing the contents of newpart appended to bytes; the caller will own the new reference. The reference to the old value of bytes will be stolen. If the new string cannot be created, the old reference to bytes will still be discarded and the value of *bytes will be set to NULL; the appropriate exception will be set.

void PyBytes_ConcatAndDel(PyObject **bytes, PyObject *newpart)

Create a new string object in *bytes containing the contents of newpart appended to bytes. This version decrements the reference count of newpart.

int _PyBytes_Resize(PyObject **bytes, Py_ssize_t newsize)

A way to resize a bytes object even though it is “immutable”. Only use this to build up a brand new bytes object; don’t use this if the bytes may already be known in other parts of the code. It is an error to call this function if the refcount on the input bytes object is not one. Pass the address of an existing bytes object as an lvalue (it may be written into), and the new size desired. On success, *bytes holds the resized bytes object and 0 is returned; the address in *bytes may differ from its input value. If the reallocation fails, the original bytes object at *bytes is deallocated, *bytes is set to NULL, a memory exception is set, and -1 is returned.