大约有 43,000 项符合查询结果（耗时：0.0284秒） [XML]
Why do we need virtual functions in C++?
...s to more general). Visa-versa you need an explicit cast, usually a dynamic_cast. Anything else - very prone to undefined behavior so make sure you know what you're doing. To the best of my knowledge, this has not changed since before even C++98.
– Steve314
Jun...
What is a good pattern for using a Global Mutex in C#?
...e : IDisposable
{
//edit by user "jitbit" - renamed private fields to "_"
public bool _hasHandle = false;
Mutex _mutex;
private void InitMutex()
{
string appGuid = ((GuidAttribute)Assembly.GetExecutingAssembly().GetCustomAttributes(typeof(GuidAttribute), false).GetValue(...
Regex lookahead, lookbehind and atomic groups
...pression.info for more details.
Positive lookahead:
Syntax:
(?=REGEX_1)REGEX_2
Match only if REGEX_1 matches; after matching REGEX_1, the match is discarded and searching for REGEX_2 starts at the same position.
example:
(?=[a-z0-9]{4}$)[a-z]{1,2}[0-9]{2,3}
REGEX_1 is [a-z0-9]{4}$ which...
Access nested dictionary items via a list of keys?
..., 'z': 3}, 'w': 3}}
Note that the Python PEP8 style guide prescribes snake_case names for functions. The above works equally well for lists or a mix of dictionaries and lists, so the names should really be get_by_path() and set_by_path():
from functools import reduce # forward compatibility for Py...
Boost.Asio的简单使用(Timer,Thread,Io_service类) - C/C++ - 清泛网 - 专注C/C++及内核技术
Boost.Asio的简单使用(Timer,Thread,Io_service类)2. 同步Timer本章介绍asio如何在定时器上进行阻塞等待(blocking wait).实现,我们包含必要的头文件.所有的asio类可以简单的通过include "...目录：
1. 同步Timer
2. 异步Timer
3. 回调函数的参数
4. 成...
sqlalchemy unique across multiple columns
... declares those in the table definition, or if using declarative as in the __table_args__:
# version1: table definition
mytable = Table('mytable', meta,
# ...
Column('customer_id', Integer, ForeignKey('customers.customer_id')),
Column('location_code', Unicode(10)),
UniqueConstraint...
How to open link in new tab on html?
...
Set the 'target' attribute of the link to _blank:
<a href="#" target="_blank" rel="noopener noreferrer">Link</a>
Edit: for other examples, see here: http://www.w3schools.com/tags/att_a_target.asp
(Note: I previously suggested blank instead of _blank beca...
Linux反编译全攻略 - 操作系统(内核) - 清泛网 - 专注C/C++及内核技术
...可以到这来下载:
http://www.crackmes.de/users/veneta/crackmes/linux_crackme_v2 。古人云“工欲善其事，必先利其器”，本文中所用到的工具及操作平台罗列如下:
操作平台: gentoo 2004.3 # kernel 2.6.9
逆向工具:
反汇编 -- objdump （这个工...
浅析为什么char类型的范围是 -128~+127 - C/C++ - 清泛网 - 专注C/C++及内核技术
...减法，它会转化为1+(-1) ,因此
0000 0001
+ 1000 0001
____________________
1000 0010 …………… -2 ，1-1= -2? 这显然是不对了，所以为了避免减法运算错误，计算机大神们发明出了反码，直接用最高位表示符号位的叫做...
Find all packages installed with easy_install/pip?
... there a way to find all Python PyPI packages that were installed with easy_install or pip? I mean, excluding everything that was/is installed with the distributions tools (in this case apt-get on Debian).
...