Context Variables Objects - Python 3.10.9 documentation 编辑
Note
Changed in version 3.7.1:In Python 3.7.1 the signatures of all context variables C APIs were changed to use PyObject
pointers instead of PyContext
, PyContextVar
, and PyContextToken
, e.g.:
// in 3.7.0: PyContext *PyContext_New(void); // in 3.7.1+: PyObject *PyContext_New(void);
See bpo-34762 for more details.
New in version 3.7.
This section details the public C API for the contextvars
module.
- type
PyContext
The C structure used to represent a
contextvars.Context
object.
- type
PyContextVar
The C structure used to represent a
contextvars.ContextVar
object.
- type
PyContextToken
The C structure used to represent a
contextvars.Token
object.
- PyTypeObject
PyContext_Type
The type object representing the context type.
- PyTypeObject
PyContextVar_Type
The type object representing the context variable type.
- PyTypeObject
PyContextToken_Type
The type object representing the context variable token type.
Type-check macros:
- int
PyContext_CheckExact
(PyObject *o) Return true if o is of type
PyContext_Type
. o must not beNULL
. This function always succeeds.
- int
PyContextVar_CheckExact
(PyObject *o) Return true if o is of type
PyContextVar_Type
. o must not beNULL
. This function always succeeds.
- int
PyContextToken_CheckExact
(PyObject *o) Return true if o is of type
PyContextToken_Type
. o must not beNULL
. This function always succeeds.
Context object management functions:
- PyObject *
PyContext_New
(void) - Return value: New reference.
Create a new empty context object. Returns
NULL
if an error has occurred.
- PyObject *
PyContext_Copy
(PyObject *ctx) - Return value: New reference.
Create a shallow copy of the passed ctx context object. Returns
NULL
if an error has occurred.
- PyObject *
PyContext_CopyCurrent
(void) - Return value: New reference.
Create a shallow copy of the current thread context. Returns
NULL
if an error has occurred.
- int
PyContext_Enter
(PyObject *ctx) Set ctx as the current context for the current thread. Returns
0
on success, and-1
on error.
- int
PyContext_Exit
(PyObject *ctx) Deactivate the ctx context and restore the previous context as the current context for the current thread. Returns
0
on success, and-1
on error.
Context variable functions:
- PyObject *
PyContextVar_New
(const char *name, PyObject *def) - Return value: New reference.
Create a new
ContextVar
object. The name parameter is used for introspection and debug purposes. The def parameter specifies a default value for the context variable, orNULL
for no default. If an error has occurred, this function returnsNULL
.
- int
PyContextVar_Get
(PyObject *var, PyObject *default_value, PyObject **value) Get the value of a context variable. Returns
-1
if an error has occurred during lookup, and0
if no error occurred, whether or not a value was found.If the context variable was found, value will be a pointer to it. If the context variable was not found, value will point to:
default_value, if not
NULL
;the default value of var, if not
NULL
;NULL
Except for
NULL
, the function returns a new reference.
如果你对这篇内容有疑问,欢迎到本站社区发帖提问 参与讨论,获取更多帮助,或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱,如果其他用户或者作者回复了您的评论,将不能在第一时间通知您!
发布评论