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问题 For purposes expressed in this question, we want to do this: typedef struct { int a; } A; typedef struct { struct { int a; }; int b; } B; A *BToA(B *b) { return (A *) b; } B *AToB(A *a) { return (B *) a; } The desire is that the casts conform to C 2011 6.7.2.1 15, which says “A pointer to a structure object, suitably converted, points to its initial member (or if that member is a bit-field, then to the unit in which it resides), and vice versa.” Since the struct { int a; } inside B does not

问题 I am having trouble calling a program with the Process class to start a program. The hierarchy to the executable is in under the bin directory while the current working directory needs to be under the lib directory. /project /bin a.out (this is what I need to call) /lib (this is where I need to be in order for a.out to work) I have set the WorkingDirectory = "path/lib" and the "FileName = "../bin/a.out" . However I am getting an error of: Unhandled Exception: System.ComponentModel

问题 I have a python project, let's call it foobar , there is a setup.py script in project root directory like all Python projects. For example foobar setup.py setup.py file content: from ez_setup import use_setuptools use_setuptools() from setuptools import setup, find_packages setup( name='foobar', version='0.0.0', packages=find_packages(), install_requires=[ 'spam==1.2.3', 'eggs>=4.5.6', ], ) I need to get dependencies information from that setup.py file using Python. The part I want would be [

问题 I am having trouble calling a program with the Process class to start a program. The hierarchy to the executable is in under the bin directory while the current working directory needs to be under the lib directory. /project /bin a.out (this is what I need to call) /lib (this is where I need to be in order for a.out to work) I have set the WorkingDirectory = "path/lib" and the "FileName = "../bin/a.out" . However I am getting an error of: Unhandled Exception: System.ComponentModel

问题 Using bitwise operator how can I test if the n least significant bits of an integer are either all sets or all not sets. For example if n = 3 I only care about the 3 least significant bits the test should return true for 0 and 7 and false for all other values between 0 and 7. Of course I could do if x = 0 or x = 7 , but I would prefer something using bitwise operators. Bonus points if the technique can be adapted to take into accounts all the bits defined by a mask. Clarification : If I

问题 I understand why using 'shell=True' can be a security risk if you have untrusted input. However, I don't understand how 'shell=False' avoids the same risks. Presumably if I wanted to allow a user to provide an input he might input: var="rm -rf /" My code might simply: subprocess.call(var,shell=True) # bad stuff Or I might do: varParts=var.split() subprocess.call(varParts,shell=False) # also bad, right? It would seem that the assumption is one wouldn't go through the trouble of processing the

问题 I am having trouble calling a program with the Process class to start a program. The hierarchy to the executable is in under the bin directory while the current working directory needs to be under the lib directory. /project /bin a.out (this is what I need to call) /lib (this is where I need to be in order for a.out to work) I have set the WorkingDirectory = "path/lib" and the "FileName = "../bin/a.out" . However I am getting an error of: Unhandled Exception: System.ComponentModel

问题 I want to be able use python descriptors in a class which has the slots optimization: class C(object): __slots__ = ['a'] a = MyDescriptor('a') def __init__(self, val): self.a = val The problem I have is how to implement the descriptor class in order to be able to store values in the class instance which invokes the descriptor object. The usual solution would look like the one below but will not work since "dict" is no longer defined when "slots" is invoked in the C class: class MyDescriptor

问题 I am getting a ReferenceError: window is not defined when using next.js with leaflet.js . Wondering if there's a simple solution to this problem - is using next.js overcomplicating my workflow? for those curious with the exact code, import React, { createRef, Component } from "react"; import L from "leaflet"; import { Map, TileLayer, Marker, Popup, DivOverlay } from "react-leaflet"; import axios from "axios"; import Header from "./Header"; export default class PDXMap extends Component { state

问题 What does the coerce argument do in django forms? I've read the documentation, but its not very helpful, so a good explanation with a few examples of use cases would be helpful. To quote the documentation: A function that takes one argument and returns a coerced value. Examples include the built-in int, float, bool and other types. Defaults to an identity function. 回答1: TypedChoiceField is just like ChoiceField, except ChoiceField always return unicode. With TypedChoiceField you pass a