8 These functions raise :exc:`TypeError` when expecting a string parameter and are
9 called with a non-string parameter.
13 These functions have been renamed to PyBytes_* in Python 3.x. Unless
14 otherwise noted, the PyBytes functions available in 3.x are aliased to their
15 PyString_* equivalents to help porting.
17 .. index:: object: string
20 .. ctype:: PyStringObject
22 This subtype of :ctype:`PyObject` represents a Python string object.
25 .. cvar:: PyTypeObject PyString_Type
27 .. index:: single: StringType (in module types)
29 This instance of :ctype:`PyTypeObject` represents the Python string type; it is
30 the same object as ``str`` and ``types.StringType`` in the Python layer. .
33 .. cfunction:: int PyString_Check(PyObject *o)
35 Return true if the object *o* is a string object or an instance of a subtype of
38 .. versionchanged:: 2.2
39 Allowed subtypes to be accepted.
42 .. cfunction:: int PyString_CheckExact(PyObject *o)
44 Return true if the object *o* is a string object, but not an instance of a
45 subtype of the string type.
50 .. cfunction:: PyObject* PyString_FromString(const char *v)
52 Return a new string object with a copy of the string *v* as value on success,
53 and *NULL* on failure. The parameter *v* must not be *NULL*; it will not be
57 .. cfunction:: PyObject* PyString_FromStringAndSize(const char *v, Py_ssize_t len)
59 Return a new string object with a copy of the string *v* as value and length
60 *len* on success, and *NULL* on failure. If *v* is *NULL*, the contents of the
61 string are uninitialized.
63 .. versionchanged:: 2.5
64 This function used an :ctype:`int` type for *len*. This might require
65 changes in your code for properly supporting 64-bit systems.
68 .. cfunction:: PyObject* PyString_FromFormat(const char *format, ...)
70 Take a C :cfunc:`printf`\ -style *format* string and a variable number of
71 arguments, calculate the size of the resulting Python string and return a string
72 with the values formatted into it. The variable arguments must be C types and
73 must correspond exactly to the format characters in the *format* string. The
74 following format characters are allowed:
76 .. % This should be exactly the same as the table in PyErr_Format.
77 .. % One should just refer to the other.
78 .. % The descriptions for %zd and %zu are wrong, but the truth is complicated
79 .. % because not all compilers support the %z width modifier -- we fake it
80 .. % when necessary via interpolating PY_FORMAT_SIZE_T.
81 .. % Similar comments apply to the %ll width modifier and
82 .. % PY_FORMAT_LONG_LONG.
83 .. % %u, %lu, %zu should have "new in Python 2.5" blurbs.
85 +-------------------+---------------+--------------------------------+
86 | Format Characters | Type | Comment |
87 +===================+===============+================================+
88 | :attr:`%%` | *n/a* | The literal % character. |
89 +-------------------+---------------+--------------------------------+
90 | :attr:`%c` | int | A single character, |
91 | | | represented as an C int. |
92 +-------------------+---------------+--------------------------------+
93 | :attr:`%d` | int | Exactly equivalent to |
94 | | | ``printf("%d")``. |
95 +-------------------+---------------+--------------------------------+
96 | :attr:`%u` | unsigned int | Exactly equivalent to |
97 | | | ``printf("%u")``. |
98 +-------------------+---------------+--------------------------------+
99 | :attr:`%ld` | long | Exactly equivalent to |
100 | | | ``printf("%ld")``. |
101 +-------------------+---------------+--------------------------------+
102 | :attr:`%lu` | unsigned long | Exactly equivalent to |
103 | | | ``printf("%lu")``. |
104 +-------------------+---------------+--------------------------------+
105 | :attr:`%lld` | long long | Exactly equivalent to |
106 | | | ``printf("%lld")``. |
107 +-------------------+---------------+--------------------------------+
108 | :attr:`%llu` | unsigned | Exactly equivalent to |
109 | | long long | ``printf("%llu")``. |
110 +-------------------+---------------+--------------------------------+
111 | :attr:`%zd` | Py_ssize_t | Exactly equivalent to |
112 | | | ``printf("%zd")``. |
113 +-------------------+---------------+--------------------------------+
114 | :attr:`%zu` | size_t | Exactly equivalent to |
115 | | | ``printf("%zu")``. |
116 +-------------------+---------------+--------------------------------+
117 | :attr:`%i` | int | Exactly equivalent to |
118 | | | ``printf("%i")``. |
119 +-------------------+---------------+--------------------------------+
120 | :attr:`%x` | int | Exactly equivalent to |
121 | | | ``printf("%x")``. |
122 +-------------------+---------------+--------------------------------+
123 | :attr:`%s` | char\* | A null-terminated C character |
125 +-------------------+---------------+--------------------------------+
126 | :attr:`%p` | void\* | The hex representation of a C |
127 | | | pointer. Mostly equivalent to |
128 | | | ``printf("%p")`` except that |
129 | | | it is guaranteed to start with |
130 | | | the literal ``0x`` regardless |
131 | | | of what the platform's |
132 | | | ``printf`` yields. |
133 +-------------------+---------------+--------------------------------+
135 An unrecognized format character causes all the rest of the format string to be
136 copied as-is to the result string, and any extra arguments discarded.
140 The `"%lld"` and `"%llu"` format specifiers are only available
141 when `HAVE_LONG_LONG` is defined.
143 .. versionchanged:: 2.7
144 Support for `"%lld"` and `"%llu"` added.
147 .. cfunction:: PyObject* PyString_FromFormatV(const char *format, va_list vargs)
149 Identical to :cfunc:`PyString_FromFormat` except that it takes exactly two
153 .. cfunction:: Py_ssize_t PyString_Size(PyObject *string)
155 Return the length of the string in string object *string*.
157 .. versionchanged:: 2.5
158 This function returned an :ctype:`int` type. This might require changes
159 in your code for properly supporting 64-bit systems.
162 .. cfunction:: Py_ssize_t PyString_GET_SIZE(PyObject *string)
164 Macro form of :cfunc:`PyString_Size` but without error checking.
166 .. versionchanged:: 2.5
167 This macro returned an :ctype:`int` type. This might require changes in
168 your code for properly supporting 64-bit systems.
171 .. cfunction:: char* PyString_AsString(PyObject *string)
173 Return a NUL-terminated representation of the contents of *string*. The pointer
174 refers to the internal buffer of *string*, not a copy. The data must not be
175 modified in any way, unless the string was just created using
176 ``PyString_FromStringAndSize(NULL, size)``. It must not be deallocated. If
177 *string* is a Unicode object, this function computes the default encoding of
178 *string* and operates on that. If *string* is not a string object at all,
179 :cfunc:`PyString_AsString` returns *NULL* and raises :exc:`TypeError`.
182 .. cfunction:: char* PyString_AS_STRING(PyObject *string)
184 Macro form of :cfunc:`PyString_AsString` but without error checking. Only
185 string objects are supported; no Unicode objects should be passed.
188 .. cfunction:: int PyString_AsStringAndSize(PyObject *obj, char **buffer, Py_ssize_t *length)
190 Return a NUL-terminated representation of the contents of the object *obj*
191 through the output variables *buffer* and *length*.
193 The function accepts both string and Unicode objects as input. For Unicode
194 objects it returns the default encoded version of the object. If *length* is
195 *NULL*, the resulting buffer may not contain NUL characters; if it does, the
196 function returns ``-1`` and a :exc:`TypeError` is raised.
198 The buffer refers to an internal string buffer of *obj*, not a copy. The data
199 must not be modified in any way, unless the string was just created using
200 ``PyString_FromStringAndSize(NULL, size)``. It must not be deallocated. If
201 *string* is a Unicode object, this function computes the default encoding of
202 *string* and operates on that. If *string* is not a string object at all,
203 :cfunc:`PyString_AsStringAndSize` returns ``-1`` and raises :exc:`TypeError`.
205 .. versionchanged:: 2.5
206 This function used an :ctype:`int *` type for *length*. This might
207 require changes in your code for properly supporting 64-bit systems.
210 .. cfunction:: void PyString_Concat(PyObject **string, PyObject *newpart)
212 Create a new string object in *\*string* containing the contents of *newpart*
213 appended to *string*; the caller will own the new reference. The reference to
214 the old value of *string* will be stolen. If the new string cannot be created,
215 the old reference to *string* will still be discarded and the value of
216 *\*string* will be set to *NULL*; the appropriate exception will be set.
219 .. cfunction:: void PyString_ConcatAndDel(PyObject **string, PyObject *newpart)
221 Create a new string object in *\*string* containing the contents of *newpart*
222 appended to *string*. This version decrements the reference count of *newpart*.
225 .. cfunction:: int _PyString_Resize(PyObject **string, Py_ssize_t newsize)
227 A way to resize a string object even though it is "immutable". Only use this to
228 build up a brand new string object; don't use this if the string may already be
229 known in other parts of the code. It is an error to call this function if the
230 refcount on the input string object is not one. Pass the address of an existing
231 string object as an lvalue (it may be written into), and the new size desired.
232 On success, *\*string* holds the resized string object and ``0`` is returned;
233 the address in *\*string* may differ from its input value. If the reallocation
234 fails, the original string object at *\*string* is deallocated, *\*string* is
235 set to *NULL*, a memory exception is set, and ``-1`` is returned.
237 .. versionchanged:: 2.5
238 This function used an :ctype:`int` type for *newsize*. This might
239 require changes in your code for properly supporting 64-bit systems.
241 .. cfunction:: PyObject* PyString_Format(PyObject *format, PyObject *args)
243 Return a new string object from *format* and *args*. Analogous to ``format %
244 args``. The *args* argument must be a tuple.
247 .. cfunction:: void PyString_InternInPlace(PyObject **string)
249 Intern the argument *\*string* in place. The argument must be the address of a
250 pointer variable pointing to a Python string object. If there is an existing
251 interned string that is the same as *\*string*, it sets *\*string* to it
252 (decrementing the reference count of the old string object and incrementing the
253 reference count of the interned string object), otherwise it leaves *\*string*
254 alone and interns it (incrementing its reference count). (Clarification: even
255 though there is a lot of talk about reference counts, think of this function as
256 reference-count-neutral; you own the object after the call if and only if you
257 owned it before the call.)
261 This function is not available in 3.x and does not have a PyBytes alias.
264 .. cfunction:: PyObject* PyString_InternFromString(const char *v)
266 A combination of :cfunc:`PyString_FromString` and
267 :cfunc:`PyString_InternInPlace`, returning either a new string object that has
268 been interned, or a new ("owned") reference to an earlier interned string object
273 This function is not available in 3.x and does not have a PyBytes alias.
276 .. cfunction:: PyObject* PyString_Decode(const char *s, Py_ssize_t size, const char *encoding, const char *errors)
278 Create an object by decoding *size* bytes of the encoded buffer *s* using the
279 codec registered for *encoding*. *encoding* and *errors* have the same meaning
280 as the parameters of the same name in the :func:`unicode` built-in function.
281 The codec to be used is looked up using the Python codec registry. Return
282 *NULL* if an exception was raised by the codec.
286 This function is not available in 3.x and does not have a PyBytes alias.
288 .. versionchanged:: 2.5
289 This function used an :ctype:`int` type for *size*. This might require
290 changes in your code for properly supporting 64-bit systems.
293 .. cfunction:: PyObject* PyString_AsDecodedObject(PyObject *str, const char *encoding, const char *errors)
295 Decode a string object by passing it to the codec registered for *encoding* and
296 return the result as Python object. *encoding* and *errors* have the same
297 meaning as the parameters of the same name in the string :meth:`encode` method.
298 The codec to be used is looked up using the Python codec registry. Return *NULL*
299 if an exception was raised by the codec.
303 This function is not available in 3.x and does not have a PyBytes alias.
306 .. cfunction:: PyObject* PyString_Encode(const char *s, Py_ssize_t size, const char *encoding, const char *errors)
308 Encode the :ctype:`char` buffer of the given size by passing it to the codec
309 registered for *encoding* and return a Python object. *encoding* and *errors*
310 have the same meaning as the parameters of the same name in the string
311 :meth:`encode` method. The codec to be used is looked up using the Python codec
312 registry. Return *NULL* if an exception was raised by the codec.
316 This function is not available in 3.x and does not have a PyBytes alias.
318 .. versionchanged:: 2.5
319 This function used an :ctype:`int` type for *size*. This might require
320 changes in your code for properly supporting 64-bit systems.
323 .. cfunction:: PyObject* PyString_AsEncodedObject(PyObject *str, const char *encoding, const char *errors)
325 Encode a string object using the codec registered for *encoding* and return the
326 result as Python object. *encoding* and *errors* have the same meaning as the
327 parameters of the same name in the string :meth:`encode` method. The codec to be
328 used is looked up using the Python codec registry. Return *NULL* if an exception
329 was raised by the codec.
333 This function is not available in 3.x and does not have a PyBytes alias.