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Batuhan Osman TASKAYA
cpython
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140d9d67
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Nis 25, 2009
tarafından
Jeroen Ruigrok van der Werven
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140d9d67
...
@@ -10,46 +10,48 @@ methods. Additional information and examples are available in
...
@@ -10,46 +10,48 @@ methods. Additional information and examples are available in
:ref:`extending-index`.
:ref:`extending-index`.
The first three of these functions described, :cfunc:`PyArg_ParseTuple`,
The first three of these functions described, :cfunc:`PyArg_ParseTuple`,
:cfunc:`PyArg_ParseTupleAndKeywords`, and :cfunc:`PyArg_Parse`, all use *format
:cfunc:`PyArg_ParseTupleAndKeywords`, and :cfunc:`PyArg_Parse`, all use
strings* which are used to tell the function about the expected arguments. The
*format strings* which are used to tell the function about the expected
format strings use the same syntax for each of these functions.
arguments. The format strings use the same syntax for each of these
functions.
A format string consists of zero or more "format units." A format unit
A format string consists of zero or more "format units." A format unit
describes one Python object; it is usually a single character or a
parenthesized
describes one Python object; it is usually a single character or a
sequence of format units. With a few exceptions, a format unit that is not a
parenthesized sequence of format units. With a few exceptions, a format unit
parenthesized sequence normally corresponds to a single address argument to
that is not a parenthesized sequence normally corresponds to a single address
these functions. In the following description, the quoted form is the format
argument to these functions. In the following description, the quoted form is
unit; the entry in (round) parentheses is the Python object type that matches
the format unit; the entry in (round) parentheses is the Python object type
th
e format unit; and the entry in [square] brackets is the type of the C
th
at matches the format unit; and the entry in [square] brackets is the type
variable(s) whose address should be passed.
of the C
variable(s) whose address should be passed.
``s`` (string or Unicode object) [const char \*]
``s`` (string or Unicode object) [const char \*]
Convert a Python string or Unicode object to a C pointer to a character
string.
Convert a Python string or Unicode object to a C pointer to a character
You must not provide storage for the string itself; a pointer to an existing
string. You must not provide storage for the string itself; a pointer to
string is stored into the character pointer variable whose address you pass.
an existing string is stored into the character pointer variable whose
The C string is NUL-terminated. The Python string must not contain embedded NUL
address you pass. The C string is NUL-terminated. The Python string must
bytes; if it does, a :exc:`TypeError` exception is raised. Unicode objects are
not contain embedded NUL bytes; if it does, a :exc:`TypeError` exception is
converted to C strings using the default encoding. If this conversion fails, a
raised. Unicode objects are converted to C strings using the default
:exc:`UnicodeError` is raised.
encoding. If this conversion fails, a
:exc:`UnicodeError` is raised.
``s#`` (string, Unicode or any read buffer compatible object) [const char \*, int (or :ctype:`Py_ssize_t`, see below)]
``s#`` (string, Unicode or any read buffer compatible object) [const char \*, int (or :ctype:`Py_ssize_t`, see below)]
This variant on ``s`` stores into two C variables, the first one a pointer
to a
This variant on ``s`` stores into two C variables, the first one a pointer
character string, the second one its length. In this case the Python string may
to a character string, the second one its length. In this case the Python
contain embedded null bytes. Unicode objects pass back a pointer to the default
string may contain embedded null bytes. Unicode objects pass back a
encoded string version of the object if such a conversion is possible. All
pointer to the default encoded string version of the object if such a
other read-buffer compatible objects pass back a reference to the raw internal
conversion is possible. All other read-buffer compatible objects pass back
data representation.
a reference to the raw internal
data representation.
Starting with Python 2.5 the type of the length argument can be
Starting with Python 2.5 the type of the length argument can be
controlled
controlled by defining the macro :cmacro:`PY_SSIZE_T_CLEAN` before
by defining the macro :cmacro:`PY_SSIZE_T_CLEAN` before including
including :file:`Python.h`. If the macro is defined, length is a
:file:`Python.h`. If the macro is defined, length is a :ctype:`Py_ssize_t`
:ctype:`Py_ssize_t`
rather than an int.
rather than an int.
``s*`` (string, Unicode, or any buffer compatible object) [Py_buffer \*]
``s*`` (string, Unicode, or any buffer compatible object) [Py_buffer \*]
Similar to ``s#``, this code fills a Py_buffer structure provided by the caller.
Similar to ``s#``, this code fills a Py_buffer structure provided by the
The buffer gets locked, so that the caller can subsequently use the buffer even
caller. The buffer gets locked, so that the caller can subsequently use
inside a ``Py_BEGIN_ALLOW_THREADS`` block; the caller is responsible for calling
the buffer even inside a ``Py_BEGIN_ALLOW_THREADS`` block; the caller is
``PyBuffer_Release`` with the structure after it has processed the data.
responsible for calling ``PyBuffer_Release`` with the structure after it
has processed the data.
.. versionadded:: 2.6
.. versionadded:: 2.6
...
@@ -66,83 +68,86 @@ variable(s) whose address should be passed.
...
@@ -66,83 +68,86 @@ variable(s) whose address should be passed.
.. versionadded:: 2.6
.. versionadded:: 2.6
``u`` (Unicode object) [Py_UNICODE \*]
``u`` (Unicode object) [Py_UNICODE \*]
Convert a Python Unicode object to a C pointer to a NUL-terminated buffer of
Convert a Python Unicode object to a C pointer to a NUL-terminated buffer
16-bit Unicode (UTF-16) data. As with ``s``, there is no need to provide
of 16-bit Unicode (UTF-16) data. As with ``s``, there is no need to
storage for the Unicode data buffer; a pointer to the existing Unicode data is
provide storage for the Unicode data buffer; a pointer to the existing
stored into the :ctype:`Py_UNICODE` pointer variable whose address you pass.
Unicode data is stored into the :ctype:`Py_UNICODE` pointer variable whose
address you pass.
``u#`` (Unicode object) [Py_UNICODE \*, int]
``u#`` (Unicode object) [Py_UNICODE \*, int]
This variant on ``u`` stores into two C variables, the first one a pointer
to a
This variant on ``u`` stores into two C variables, the first one a pointer
Unicode data buffer, the second one its length. Non-Unicode objects are handled
to a Unicode data buffer, the second one its length. Non-Unicode objects
by interpreting their read-buffer pointer as pointer to a :ctype:`Py_UNICODE`
are handled by interpreting their read-buffer pointer as pointer to a
array.
:ctype:`Py_UNICODE`
array.
``es`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer]
``es`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer]
This variant on ``s`` is used for encoding Unicode and objects convertible
to
This variant on ``s`` is used for encoding Unicode and objects convertible
Unicode into a character buffer. It only works for encoded data without embedded
to Unicode into a character buffer. It only works for encoded data without
NUL bytes.
embedded
NUL bytes.
This format requires two arguments. The first is only used as input, and
This format requires two arguments. The first is only used as input, and
must be a :ctype:`const char\*` which points to the name of an encoding as a
must be a :ctype:`const char\*` which points to the name of an encoding as
NUL-terminated string, or *NULL*, in which case the default encoding is used.
a NUL-terminated string, or *NULL*, in which case the default encoding is
An exception is raised if the named encoding is not known to Python. The
used. An exception is raised if the named encoding is not known to Python.
second argument must be a :ctype:`char\*\*`; the value of the pointer it
The second argument must be a :ctype:`char\*\*`; the value of the pointer
references will be set to a buffer with the contents of the argument text.
it references will be set to a buffer with the contents of the argument
The text will be encoded in the encoding specified by the first argument.
text. The text will be encoded in the encoding specified by the first
argument.
:cfunc:`PyArg_ParseTuple` will allocate a buffer of the needed size, copy the
encoded data into this buffer and adjust *\*buffer* to reference the newly
:cfunc:`PyArg_ParseTuple` will allocate a buffer of the needed size, copy
allocated storage. The caller is responsible for calling :cfunc:`PyMem_Free` to
the encoded data into this buffer and adjust *\*buffer* to reference the
free the allocated buffer after use.
newly allocated storage. The caller is responsible for calling
:cfunc:`PyMem_Free` to free the allocated buffer after use.
``et`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer]
``et`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer]
Same as ``es`` except that 8-bit string objects are passed through without
Same as ``es`` except that 8-bit string objects are passed through without
recoding them. Instead, the implementation assumes that the string object
uses
recoding them. Instead, the implementation assumes that the string object
the encoding passed in as parameter.
uses
the encoding passed in as parameter.
``es#`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer, int \*buffer_length]
``es#`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer, int \*buffer_length]
This variant on ``s#`` is used for encoding Unicode and objects convertible
to
This variant on ``s#`` is used for encoding Unicode and objects convertible
Unicode into a character buffer. Unlike the ``es`` format, this variant allows
to Unicode into a character buffer. Unlike the ``es`` format, this variant
input data which contains NUL characters.
allows
input data which contains NUL characters.
It requires three arguments. The first is only used as input, and must be
a
It requires three arguments. The first is only used as input, and must be
:ctype:`const char\*` which points to the name of an encoding as a
a
:ctype:`const char\*` which points to the name of an encoding as a
NUL-terminated string, or *NULL*, in which case the default encoding is
used.
NUL-terminated string, or *NULL*, in which case the default encoding is
An exception is raised if the named encoding is not known to Python. The
used. An exception is raised if the named encoding is not known to Python.
second argument must be a :ctype:`char\*\*`; the value of the pointer it
The second argument must be a :ctype:`char\*\*`; the value of the pointer
references will be set to a buffer with the contents of the argument text.
it references will be set to a buffer with the contents of the argument
The text will be encoded in the encoding specified by the first argument.
text. The text will be encoded in the encoding specified by the first
The third argument must be a pointer to an integer; the referenced integer
argument. The third argument must be a pointer to an integer; the
will be set to the number of bytes in the output buffer.
referenced integer
will be set to the number of bytes in the output buffer.
There are two modes of operation:
There are two modes of operation:
If *\*buffer* points a *NULL* pointer, the function will allocate a buffer of
If *\*buffer* points a *NULL* pointer, the function will allocate a buffer
the needed size, copy the encoded data into this buffer and set *\*buffer* to
of the needed size, copy the encoded data into this buffer and set
reference the newly allocated storage. The caller is responsible for calling
*\*buffer* to reference the newly allocated storage. The caller is
:cfunc:`PyMem_Free` to free the allocated buffer after usage.
responsible for calling :cfunc:`PyMem_Free` to free the allocated buffer
after usage.
If *\*buffer* points to a non-*NULL* pointer (an already allocated buffer),
If *\*buffer* points to a non-*NULL* pointer (an already allocated buffer),
:cfunc:`PyArg_ParseTuple` will use this location as the buffer and
interpret the
:cfunc:`PyArg_ParseTuple` will use this location as the buffer and
in
itial value of *\*buffer_length* as the buffer size. It will then copy the
in
terpret the initial value of *\*buffer_length* as the buffer size. It
encoded data into the buffer and NUL-terminate it. If the buffer is not large
will then copy the encoded data into the buffer and NUL-terminate it. If
enough, a :exc:`ValueError` will be set.
the buffer is not large
enough, a :exc:`ValueError` will be set.
In both cases, *\*buffer_length* is set to the length of the encoded data
In both cases, *\*buffer_length* is set to the length of the encoded data
without the trailing NUL byte.
without the trailing NUL byte.
``et#`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer]
``et#`` (string, Unicode object or character buffer compatible object) [const char \*encoding, char \*\*buffer]
Same as ``es#`` except that string objects are passed through without
recoding
Same as ``es#`` except that string objects are passed through without
them. Instead, the implementation assumes that the string object uses the
recoding them. Instead, the implementation assumes that the string object
encoding passed in as parameter.
uses the
encoding passed in as parameter.
``b`` (integer) [unsigned char]
``b`` (integer) [unsigned char]
Convert a nonnegative Python integer to an unsigned tiny int, stored in a C
Convert a nonnegative Python integer to an unsigned tiny int, stored in a C
:ctype:`unsigned char`.
:ctype:`unsigned char`.
``B`` (integer) [unsigned char]
``B`` (integer) [unsigned char]
Convert a Python integer to a tiny int without overflow checking, stored in
a C
Convert a Python integer to a tiny int without overflow checking, stored in
:ctype:`unsigned char`.
a C
:ctype:`unsigned char`.
.. versionadded:: 2.3
.. versionadded:: 2.3
...
@@ -150,8 +155,8 @@ variable(s) whose address should be passed.
...
@@ -150,8 +155,8 @@ variable(s) whose address should be passed.
Convert a Python integer to a C :ctype:`short int`.
Convert a Python integer to a C :ctype:`short int`.
``H`` (integer) [unsigned short int]
``H`` (integer) [unsigned short int]
Convert a Python integer to a C :ctype:`unsigned short int`, without
overflow
Convert a Python integer to a C :ctype:`unsigned short int`, without
checking.
overflow
checking.
.. versionadded:: 2.3
.. versionadded:: 2.3
...
@@ -168,20 +173,21 @@ variable(s) whose address should be passed.
...
@@ -168,20 +173,21 @@ variable(s) whose address should be passed.
Convert a Python integer to a C :ctype:`long int`.
Convert a Python integer to a C :ctype:`long int`.
``k`` (integer) [unsigned long]
``k`` (integer) [unsigned long]
Convert a Python integer or long integer to a C :ctype:`unsigned long`
without
Convert a Python integer or long integer to a C :ctype:`unsigned long`
overflow checking.
without
overflow checking.
.. versionadded:: 2.3
.. versionadded:: 2.3
``L`` (integer) [PY_LONG_LONG]
``L`` (integer) [PY_LONG_LONG]
Convert a Python integer to a C :ctype:`long long`. This format is only
Convert a Python integer to a C :ctype:`long long`. This format is only
available on platforms that support :ctype:`long long` (or :ctype:`_int64`
on
available on platforms that support :ctype:`long long` (or :ctype:`_int64`
Windows).
on
Windows).
``K`` (integer) [unsigned PY_LONG_LONG]
``K`` (integer) [unsigned PY_LONG_LONG]
Convert a Python integer or long integer to a C :ctype:`unsigned long long`
Convert a Python integer or long integer to a C :ctype:`unsigned long long`
without overflow checking. This format is only available on platforms that
without overflow checking. This format is only available on platforms that
support :ctype:`unsigned long long` (or :ctype:`unsigned _int64` on Windows).
support :ctype:`unsigned long long` (or :ctype:`unsigned _int64` on
Windows).
.. versionadded:: 2.3
.. versionadded:: 2.3
...
@@ -204,60 +210,61 @@ variable(s) whose address should be passed.
...
@@ -204,60 +210,61 @@ variable(s) whose address should be passed.
Convert a Python complex number to a C :ctype:`Py_complex` structure.
Convert a Python complex number to a C :ctype:`Py_complex` structure.
``O`` (object) [PyObject \*]
``O`` (object) [PyObject \*]
Store a Python object (without any conversion) in a C object pointer. The
C
Store a Python object (without any conversion) in a C object pointer. The
program thus receives the actual object that was passed. The object's reference
C program thus receives the actual object that was passed. The object's
count is not increased. The pointer stored is not *NULL*.
reference
count is not increased. The pointer stored is not *NULL*.
``O!`` (object) [*typeobject*, PyObject \*]
``O!`` (object) [*typeobject*, PyObject \*]
Store a Python object in a C object pointer. This is similar to ``O``, but
Store a Python object in a C object pointer. This is similar to ``O``, but
takes two C arguments: the first is the address of a Python type object,
the
takes two C arguments: the first is the address of a Python type object,
second is the address of the C variable (of type :ctype:`PyObject\*`) into which
the second is the address of the C variable (of type :ctype:`PyObject\*`)
the object pointer is stored. If the Python object does not have the required
into which the object pointer is stored. If the Python object does not
type, :exc:`TypeError` is raised.
have the required
type, :exc:`TypeError` is raised.
``O&`` (object) [*converter*, *anything*]
``O&`` (object) [*converter*, *anything*]
Convert a Python object to a C variable through a *converter* function.
This
Convert a Python object to a C variable through a *converter* function.
takes two arguments: the first is a function, the second is the address of a C
This takes two arguments: the first is a function, the second is the
variable (of arbitrary type), converted to :ctype:`void \*`. The *converter*
address of a C variable (of arbitrary type), converted to :ctype:`void \*`.
function in turn is called as follows::
The *converter*
function in turn is called as follows::
status = converter(object, address);
status = converter(object, address);
where *object* is the Python object to be converted and *address* is the
where *object* is the Python object to be converted and *address* is the
:ctype:`void\*` argument that was passed to the :cfunc:`PyArg_Parse\*` function.
:ctype:`void\*` argument that was passed to the :cfunc:`PyArg_Parse\*`
The returned *status* should be ``1`` for a successful conversion and ``0`` if
function. The returned *status* should be ``1`` for a successful
the conversion has failed. When the conversion fails, the *converter* function
conversion and ``0`` if the conversion has failed. When the conversion
should raise an exception and leave the content of *address* unmodified.
fails, the *converter* function should raise an exception and leave the
content of *address* unmodified.
``S`` (string) [PyStringObject \*]
``S`` (string) [PyStringObject \*]
Like ``O`` but requires that the Python object is a string object. Raises
Like ``O`` but requires that the Python object is a string object. Raises
:exc:`TypeError` if the object is not a string object. The C variable may
also
:exc:`TypeError` if the object is not a string object. The C variable may
be declared as :ctype:`PyObject\*`.
also
be declared as :ctype:`PyObject\*`.
``U`` (Unicode string) [PyUnicodeObject \*]
``U`` (Unicode string) [PyUnicodeObject \*]
Like ``O`` but requires that the Python object is a Unicode object. Raises
Like ``O`` but requires that the Python object is a Unicode object. Raises
:exc:`TypeError` if the object is not a Unicode object. The C variable may
also
:exc:`TypeError` if the object is not a Unicode object. The C variable may
be declared as :ctype:`PyObject\*`.
also
be declared as :ctype:`PyObject\*`.
``t#`` (read-only character buffer) [char \*, int]
``t#`` (read-only character buffer) [char \*, int]
Like ``s#``, but accepts any object which implements the read-only buffer
Like ``s#``, but accepts any object which implements the read-only buffer
interface. The :ctype:`char\*` variable is set to point to the first byte
of
interface. The :ctype:`char\*` variable is set to point to the first byte
the buffer, and the :ctype:`int` is set to the length of the buffer. Only
of the buffer, and the :ctype:`int` is set to the length of the buffer.
single-segment buffer objects are accepted; :exc:`TypeError` is raised for all
Only single-segment buffer objects are accepted; :exc:`TypeError` is raised
others.
for all
others.
``w`` (read-write character buffer) [char \*]
``w`` (read-write character buffer) [char \*]
Similar to ``s``, but accepts any object which implements the read-write
buffer
Similar to ``s``, but accepts any object which implements the read-write
interface. The caller must determine the length of the buffer by other means,
buffer interface. The caller must determine the length of the buffer by
o
r use ``w#`` instead. Only single-segment buffer objects are accepted;
o
ther means, or use ``w#`` instead. Only single-segment buffer objects are
:exc:`TypeError` is raised for all others.
accepted;
:exc:`TypeError` is raised for all others.
``w#`` (read-write character buffer) [char \*, Py_ssize_t]
``w#`` (read-write character buffer) [char \*, Py_ssize_t]
Like ``s#``, but accepts any object which implements the read-write buffer
Like ``s#``, but accepts any object which implements the read-write buffer
interface. The :ctype:`char \*` variable is set to point to the first byte
of
interface. The :ctype:`char \*` variable is set to point to the first byte
the buffer, and the :ctype:`int` is set to the length of the buffer. Only
of the buffer, and the :ctype:`int` is set to the length of the buffer.
single-segment buffer objects are accepted; :exc:`TypeError` is raised for all
Only single-segment buffer objects are accepted; :exc:`TypeError` is raised
others.
for all
others.
``w*`` (read-write byte-oriented buffer) [Py_buffer \*]
``w*`` (read-write byte-oriented buffer) [Py_buffer \*]
This is to ``w`` what ``s*`` is to ``s``.
This is to ``w`` what ``s*`` is to ``s``.
...
@@ -265,72 +272,72 @@ variable(s) whose address should be passed.
...
@@ -265,72 +272,72 @@ variable(s) whose address should be passed.
.. versionadded:: 2.6
.. versionadded:: 2.6
``(items)`` (tuple) [*matching-items*]
``(items)`` (tuple) [*matching-items*]
The object must be a Python sequence whose length is the number of format
units
The object must be a Python sequence whose length is the number of format
in *items*. The C arguments must correspond to the individual format units in
units in *items*. The C arguments must correspond to the individual format
*items*. Format units for sequences may be nested.
units in
*items*. Format units for sequences may be nested.
.. note::
.. note::
Prior to Python version 1.5.2, this format specifier only accepted a tuple
Prior to Python version 1.5.2, this format specifier only accepted a
containing the individual parameters, not an arbitrary sequence. Code which
tuple containing the individual parameters, not an arbitrary sequence.
previously caused :exc:`TypeError` to be raised here may now proceed without an
Code which previously caused :exc:`TypeError` to be raised here may now
exception. This is not expected to be a problem for existing code.
proceed without an exception. This is not expected to be a problem for
existing code.
It is possible to pass Python long integers where integers are requested;
It is possible to pass Python long integers where integers are requested;
however no proper range checking is done --- the most significant bits are
however no proper range checking is done --- the most significant bits are
silently truncated when the receiving field is too small to receive the value
silently truncated when the receiving field is too small to receive the value
(actually, the semantics are inherited from downcasts in C --- your mileage
may
(actually, the semantics are inherited from downcasts in C --- your mileage
vary).
may
vary).
A few other characters have a meaning in a format string. These may not occur
A few other characters have a meaning in a format string. These may not occur
inside nested parentheses. They are:
inside nested parentheses. They are:
``|``
``|``
Indicates that the remaining arguments in the Python argument list are
optional.
Indicates that the remaining arguments in the Python argument list are
The C variables corresponding to optional arguments should be initialized to
optional. The C variables corresponding to optional arguments should be
their default value --- when an optional argument is not specified,
initialized to their default value --- when an optional argument is not
:cfunc:`PyArg_ParseTuple` does not touch the contents of the corresponding C
specified, :cfunc:`PyArg_ParseTuple` does not touch the contents of the
variable(s).
corresponding C
variable(s).
``:``
``:``
The list of format units ends here; the string after the colon is used as
the
The list of format units ends here; the string after the colon is used as
function name in error messages (the "associated value" of the exception that
the function name in error messages (the "associated value" of the
:cfunc:`PyArg_ParseTuple` raises).
exception that
:cfunc:`PyArg_ParseTuple` raises).
``;``
``;``
The list of format units ends here; the string after the semicolon is used
as
The list of format units ends here; the string after the semicolon is used
the error message *instead* of the default error message. ``:`` and ``;``
as the error message *instead* of the default error message. ``:`` and
mutually exclude each other.
``;``
mutually exclude each other.
Note that any Python object references which are provided to the caller are
Note that any Python object references which are provided to the caller are
*borrowed* references; do not decrement their reference count!
*borrowed* references; do not decrement their reference count!
Additional arguments passed to these functions must be addresses of variables
Additional arguments passed to these functions must be addresses of variables
whose type is determined by the format string; these are used to store values
whose type is determined by the format string; these are used to store values
from the input tuple. There are a few cases, as described in the list of format
from the input tuple. There are a few cases, as described in the list of
units above, where these parameters are used as input values; they should match
format units above, where these parameters are used as input values; they
what is specified for the corresponding format unit in that case.
should match what is specified for the corresponding format unit in that case.
For the conversion to succeed, the *arg* object must match the format
For the conversion to succeed, the *arg* object must match the format and the
and the format must be exhausted. On success, the
format must be exhausted. On success, the :cfunc:`PyArg_Parse\*` functions
:cfunc:`PyArg_Parse\*` functions return true, otherwise they return
return true, otherwise they return false and raise an appropriate exception.
false and raise an appropriate exception. When the
When the :cfunc:`PyArg_Parse\*` functions fail due to conversion failure in
:cfunc:`PyArg_Parse\*` functions fail due to conversion failure in one
one of the format units, the variables at the addresses corresponding to that
of the format units, the variables at the addresses corresponding to that
and the following format units are left untouched.
and the following format units are left untouched.
.. cfunction:: int PyArg_ParseTuple(PyObject *args, const char *format, ...)
.. cfunction:: int PyArg_ParseTuple(PyObject *args, const char *format, ...)
Parse the parameters of a function that takes only positional parameters
into
Parse the parameters of a function that takes only positional parameters
local variables. Returns true on success; on failure, it returns false and
into local variables. Returns true on success; on failure, it returns
raises the appropriate exception.
false and
raises the appropriate exception.
.. cfunction:: int PyArg_VaParse(PyObject *args, const char *format, va_list vargs)
.. cfunction:: int PyArg_VaParse(PyObject *args, const char *format, va_list vargs)
Identical to :cfunc:`PyArg_ParseTuple`, except that it accepts a va_list
rather
Identical to :cfunc:`PyArg_ParseTuple`, except that it accepts a va_list
than a variable number of arguments.
rather
than a variable number of arguments.
.. cfunction:: int PyArg_ParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char *keywords[], ...)
.. cfunction:: int PyArg_ParseTupleAndKeywords(PyObject *args, PyObject *kw, const char *format, char *keywords[], ...)
...
@@ -348,32 +355,33 @@ and the following format units are left untouched.
...
@@ -348,32 +355,33 @@ and the following format units are left untouched.
.. cfunction:: int PyArg_Parse(PyObject *args, const char *format, ...)
.. cfunction:: int PyArg_Parse(PyObject *args, const char *format, ...)
Function used to deconstruct the argument lists of "old-style" functions ---
Function used to deconstruct the argument lists of "old-style" functions
these are functions which use the :const:`METH_OLDARGS` parameter parsing
--- these are functions which use the :const:`METH_OLDARGS` parameter
method. This is not recommended for use in parameter parsing in new code, and
parsing method. This is not recommended for use in parameter parsing in
most code in the standard interpreter has been modified to no longer use this
new code, and most code in the standard interpreter has been modified to no
for that purpose. It does remain a convenient way to decompose other tuples,
longer use this for that purpose. It does remain a convenient way to
however, and may continue to be used for that purpose.
decompose other tuples, however, and may continue to be used for that
purpose.
.. cfunction:: int PyArg_UnpackTuple(PyObject *args, const char *name, Py_ssize_t min, Py_ssize_t max, ...)
.. cfunction:: int PyArg_UnpackTuple(PyObject *args, const char *name, Py_ssize_t min, Py_ssize_t max, ...)
A simpler form of parameter retrieval which does not use a format string to
A simpler form of parameter retrieval which does not use a format string to
specify the types of the arguments. Functions which use this method to
retrieve
specify the types of the arguments. Functions which use this method to
their parameters should be declared as :const:`METH_VARARGS` in function or
retrieve their parameters should be declared as :const:`METH_VARARGS` in
method tables. The tuple containing the actual parameters should be passed a
s
function or method tables. The tuple containing the actual parameter
s
*args*; it must actually be a tuple. The length of the tuple must be at least
should be passed as *args*; it must actually be a tuple. The length of the
*min* and no more than *max*; *min* and *max* may be equal. Additional
tuple must be at least *min* and no more than *max*; *min* and *max* may be
arguments must be passed to the function, each of which should be a pointer to a
equal. Additional arguments must be passed to the function, each of which
:ctype:`PyObject\*` variable; these will be filled in with the values from
should be a pointer to a :ctype:`PyObject\*` variable; these will be filled
*args*; they will contain borrowed references. The variables which correspond
in with the values from *args*; they will contain borrowed references. The
to optional parameters not given by *args* will not be filled in; these should
variables which correspond to optional parameters not given by *args* will
be initialized by the caller. This function returns true on success and false if
not be filled in; these should be initialized by the caller. This function
*args* is not a tuple or contains the wrong number of elements; an exception
returns true on success and false if *args* is not a tuple or contains the
will be set if there was a failure.
w
rong number of elements; an exception w
ill be set if there was a failure.
This is an example of the use of this function, taken from the sources for
the
This is an example of the use of this function, taken from the sources for
:mod:`_weakref` helper module for weak references::
the
:mod:`_weakref` helper module for weak references::
static PyObject *
static PyObject *
weakref_ref(PyObject *self, PyObject *args)
weakref_ref(PyObject *self, PyObject *args)
...
@@ -388,8 +396,8 @@ and the following format units are left untouched.
...
@@ -388,8 +396,8 @@ and the following format units are left untouched.
return result;
return result;
}
}
The call to :cfunc:`PyArg_UnpackTuple` in this example is entirely
equivalent to
The call to :cfunc:`PyArg_UnpackTuple` in this example is entirely
this call to :cfunc:`PyArg_ParseTuple`::
equivalent to
this call to :cfunc:`PyArg_ParseTuple`::
PyArg_ParseTuple(args, "O|O:ref", &object, &callback)
PyArg_ParseTuple(args, "O|O:ref", &object, &callback)
...
@@ -398,40 +406,42 @@ and the following format units are left untouched.
...
@@ -398,40 +406,42 @@ and the following format units are left untouched.
.. cfunction:: PyObject* Py_BuildValue(const char *format, ...)
.. cfunction:: PyObject* Py_BuildValue(const char *format, ...)
Create a new value based on a format string similar to those accepted by the
Create a new value based on a format string similar to those accepted by
:cfunc:`PyArg_Parse\*` family of functions and a sequence of values. Returns
the :cfunc:`PyArg_Parse\*` family of functions and a sequence of values.
the value or *NULL* in the case of an error; an exception will be raised if
Returns the value or *NULL* in the case of an error; an exception will be
*NULL* is returned.
raised if *NULL* is returned.
:cfunc:`Py_BuildValue` does not always build a tuple. It builds a tuple only if
:cfunc:`Py_BuildValue` does not always build a tuple. It builds a tuple
its format string contains two or more format units. If the format string is
only if its format string contains two or more format units. If the format
empty, it returns ``None``; if it contains exactly one format unit, it returns
string is empty, it returns ``None``; if it contains exactly one format
whatever object is described by that format unit. To force it to return a tuple
unit, it returns whatever object is described by that format unit. To
of size 0 or one, parenthesize the format string.
force it to return a tuple of size 0 or one, parenthesize the format
string.
When memory buffers are passed as parameters to supply data to build objects, as
for the ``s`` and ``s#`` formats, the required data is copied. Buffers provided
When memory buffers are passed as parameters to supply data to build
by the caller are never referenced by the objects created by
objects, as for the ``s`` and ``s#`` formats, the required data is copied.
:cfunc:`Py_BuildValue`. In other words, if your code invokes :cfunc:`malloc`
Buffers provided by the caller are never referenced by the objects created
and passes the allocated memory to :cfunc:`Py_BuildValue`, your code is
by :cfunc:`Py_BuildValue`. In other words, if your code invokes
responsible for calling :cfunc:`free` for that memory once
:cfunc:`malloc` and passes the allocated memory to :cfunc:`Py_BuildValue`,
your code is responsible for calling :cfunc:`free` for that memory once
:cfunc:`Py_BuildValue` returns.
:cfunc:`Py_BuildValue` returns.
In the following description, the quoted form is the format unit; the entry in
In the following description, the quoted form is the format unit; the entry
(round) parentheses is the Python object type that the format unit will return;
in (round) parentheses is the Python object type that the format unit will
and the entry in [square] brackets is the type of the C value(s) to be passed.
return; and the entry in [square] brackets is the type of the C value(s) to
be passed.
The characters space, tab, colon and comma are ignored in format strings
(but
The characters space, tab, colon and comma are ignored in format strings
not within format units such as ``s#``). This can be used to make long format
(but not within format units such as ``s#``). This can be used to make
strings a tad more readable.
long format
strings a tad more readable.
``s`` (string) [char \*]
``s`` (string) [char \*]
Convert a null-terminated C string to a Python object. If the C string
pointer
Convert a null-terminated C string to a Python object. If the C string
is *NULL*, ``None`` is used.
pointer
is *NULL*, ``None`` is used.
``s#`` (string) [char \*, int]
``s#`` (string) [char \*, int]
Convert a C string and its length to a Python object. If the C string
pointer
Convert a C string and its length to a Python object. If the C string
is *NULL*, the length is ignored and ``None`` is returned.
pointer
is *NULL*, the length is ignored and ``None`` is returned.
``z`` (string or ``None``) [char \*]
``z`` (string or ``None``) [char \*]
Same as ``s``.
Same as ``s``.
...
@@ -440,13 +450,14 @@ and the following format units are left untouched.
...
@@ -440,13 +450,14 @@ and the following format units are left untouched.
Same as ``s#``.
Same as ``s#``.
``u`` (Unicode string) [Py_UNICODE \*]
``u`` (Unicode string) [Py_UNICODE \*]
Convert a null-terminated buffer of Unicode (UCS-2 or UCS-4) data to a Python
Convert a null-terminated buffer of Unicode (UCS-2 or UCS-4) data to a
Unicode object. If the Unicode buffer pointer is *NULL*, ``None`` is returned.
Python Unicode object. If the Unicode buffer pointer is *NULL*,
``None`` is returned.
``u#`` (Unicode string) [Py_UNICODE \*, int]
``u#`` (Unicode string) [Py_UNICODE \*, int]
Convert a Unicode (UCS-2 or UCS-4) data buffer and its length to a
Python
Convert a Unicode (UCS-2 or UCS-4) data buffer and its length to a
Unicode object. If the Unicode buffer pointer is *NULL*, the length is ignored
Python Unicode object. If the Unicode buffer pointer is *NULL*, the
and ``None`` is returned.
length is ignored
and ``None`` is returned.
``i`` (integer) [int]
``i`` (integer) [int]
Convert a plain C :ctype:`int` to a Python integer object.
Convert a plain C :ctype:`int` to a Python integer object.
...
@@ -467,20 +478,20 @@ and the following format units are left untouched.
...
@@ -467,20 +478,20 @@ and the following format units are left untouched.
Convert a C :ctype:`unsigned short int` to a Python integer object.
Convert a C :ctype:`unsigned short int` to a Python integer object.
``I`` (integer/long) [unsigned int]
``I`` (integer/long) [unsigned int]
Convert a C :ctype:`unsigned int` to a Python integer object or a Python
long
Convert a C :ctype:`unsigned int` to a Python integer object or a Python
integer object, if it is larger than ``sys.maxint``.
long
integer object, if it is larger than ``sys.maxint``.
``k`` (integer/long) [unsigned long]
``k`` (integer/long) [unsigned long]
Convert a C :ctype:`unsigned long` to a Python integer object or a
Python long
Convert a C :ctype:`unsigned long` to a Python integer object or a
integer object, if it is larger than ``sys.maxint``.
Python long
integer object, if it is larger than ``sys.maxint``.
``L`` (long) [PY_LONG_LONG]
``L`` (long) [PY_LONG_LONG]
Convert a C :ctype:`long long` to a Python long integer object. Only
available
Convert a C :ctype:`long long` to a Python long integer object. Only
on platforms that support :ctype:`long long`.
available
on platforms that support :ctype:`long long`.
``K`` (long) [unsigned PY_LONG_LONG]
``K`` (long) [unsigned PY_LONG_LONG]
Convert a C :ctype:`unsigned long long` to a Python long integer object.
Only
Convert a C :ctype:`unsigned long long` to a Python long integer object.
available on platforms that support :ctype:`unsigned long long`.
Only
available on platforms that support :ctype:`unsigned long long`.
``n`` (int) [Py_ssize_t]
``n`` (int) [Py_ssize_t]
Convert a C :ctype:`Py_ssize_t` to a Python integer or long integer.
Convert a C :ctype:`Py_ssize_t` to a Python integer or long integer.
...
@@ -488,8 +499,8 @@ and the following format units are left untouched.
...
@@ -488,8 +499,8 @@ and the following format units are left untouched.
.. versionadded:: 2.5
.. versionadded:: 2.5
``c`` (string of length 1) [char]
``c`` (string of length 1) [char]
Convert a C :ctype:`int` representing a character to a Python string of
length
Convert a C :ctype:`int` representing a character to a Python string of
1.
length
1.
``d`` (float) [double]
``d`` (float) [double]
Convert a C :ctype:`double` to a Python floating point number.
Convert a C :ctype:`double` to a Python floating point number.
...
@@ -502,39 +513,41 @@ and the following format units are left untouched.
...
@@ -502,39 +513,41 @@ and the following format units are left untouched.
``O`` (object) [PyObject \*]
``O`` (object) [PyObject \*]
Pass a Python object untouched (except for its reference count, which is
Pass a Python object untouched (except for its reference count, which is
incremented by one). If the object passed in is a *NULL* pointer, it is
assumed
incremented by one). If the object passed in is a *NULL* pointer, it is
that this was caused because the call producing the argument found an error and
assumed that this was caused because the call producing the argument
set an exception. Therefore, :cfunc:`Py_BuildValue` will return *NULL* but won't
found an error and set an exception. Therefore, :cfunc:`Py_BuildValue`
raise an exception. If no exception has been raised yet, :exc:`SystemError` i
s
will return *NULL* but won't raise an exception. If no exception ha
s
set.
been raised yet, :exc:`SystemError` is
set.
``S`` (object) [PyObject \*]
``S`` (object) [PyObject \*]
Same as ``O``.
Same as ``O``.
``N`` (object) [PyObject \*]
``N`` (object) [PyObject \*]
Same as ``O``, except it doesn't increment the reference count on the
object.
Same as ``O``, except it doesn't increment the reference count on the
Useful when the object is created by a call to an object constructor in the
object. Useful when the object is created by a call to an object
argument list.
constructor in the
argument list.
``O&`` (object) [*converter*, *anything*]
``O&`` (object) [*converter*, *anything*]
Convert *anything* to a Python object through a *converter* function.
The
Convert *anything* to a Python object through a *converter* function.
function is called with *anything* (which should be compatible with :ctype:`void
The function is called with *anything* (which should be compatible with
\*`) as its argument and should return a "new" Python object, or *NULL* if a
n
:ctype:`void \*`) as its argument and should return a "new" Pytho
n
error occurred.
object, or *NULL* if an
error occurred.
``(items)`` (tuple) [*matching-items*]
``(items)`` (tuple) [*matching-items*]
Convert a sequence of C values to a Python tuple with the same number of items.
Convert a sequence of C values to a Python tuple with the same number of
items.
``[items]`` (list) [*matching-items*]
``[items]`` (list) [*matching-items*]
Convert a sequence of C values to a Python list with the same number of items.
Convert a sequence of C values to a Python list with the same number of
items.
``{items}`` (dictionary) [*matching-items*]
``{items}`` (dictionary) [*matching-items*]
Convert a sequence of C values to a Python dictionary. Each pair of
consecutive
Convert a sequence of C values to a Python dictionary. Each pair of
C values adds one item to the dictionary, serving as key and value,
consecutive C values adds one item to the dictionary, serving as key and
respectively.
value,
respectively.
If there is an error in the format string, the :exc:`SystemError` exception
is
If there is an error in the format string, the :exc:`SystemError` exception
set and *NULL* returned.
is
set and *NULL* returned.
.. cfunction:: PyObject* Py_VaBuildValue(const char *format, va_list vargs)
.. cfunction:: PyObject* Py_VaBuildValue(const char *format, va_list vargs)
...
...
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