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Why does volatile exist?
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Some processors have floating point registers that have more than 64 bits of precision (eg. 32-bit x86 without SSE, see Peter's comment). That way, if you run several operations on double-precision numbers, you actually get a higher-precision answer than if you were to truncate each interm...
How do you trigger a block after a delay, like -performSelector:withObject:afterDelay:?
....42
// Delay 2 seconds
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, Int64(2.0 * Double(NSEC_PER_SEC))), dispatch_get_main_queue()) { () -> Void in
println("Sum of times: \(time1 + time2)")
}
Objective C
CGFloat time1 = 3.49;
CGFloat time2 = 8.13;
// Delay 2 seconds
dispatch_after(...
实战Nginx与PHP（FastCGI）的安装、配置与优化 - 更多技术 - 清泛网 - 专注...
...程数。根据官方建议，小于2GB内存的服务器，可以只开启64个进程，4GB以上内存的服务器可以开启200个进程。
<value name="max_children">5</value>
标签request_terminate_timeout用于设置FastCGI执行脚本的时间。默认是0s，也就是无限执行下...
CentOS 6.4下Squid代理服务器的安装与配置 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...：CentOS release 6.4 (Final)
Squid版本：squid-3.1.10-20.el6_5.3.x86_64
SELINUX=disabled
HTTP Service: stoped
三、安装Squid服务
3.1 检查squid软件是否安装
# rpm -qa|grep squid
3.2 如果未安装，则使用yum 方式安装
# yum -y install squid
3.3 设置开机自启动
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Unique random string generation
...ething looking like your example, you probably want to convert it to a Base64 string:
Guid g = Guid.NewGuid();
string GuidString = Convert.ToBase64String(g.ToByteArray());
GuidString = GuidString.Replace("=","");
GuidString = GuidString.Replace("+","");
I get rid of "=" and "+" to...
Apache两种工作模式区别及配置切换 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...作模式详解：
http://www.cnblogs.com/ghj1976/archive/2011/01/11/1932764.html
prefork的工作原理及配置
如果不用“--with-mpm”显式指定某种MPM，prefork就是Unix平台上缺省的MPM。它所采用的预派生子进程方式也是Apache 1.3中采用的模式。prefork...
Two-way encryption: I need to store passwords that can be retrieved
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$salt = substr($data, 0, 128);
$enc = substr($data, 128, -64);
$mac = substr($data, -64);
list ($cipherKey, $macKey, $iv) = $this->getKeys($salt, $key);
if (!hash_equals(hash_hmac('sha512', $enc, $macKey, true), $mac)) {
return false;
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.htaccess: Invalid command 'RewriteEngine', perhaps misspelled or defined by a module not included i
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Steps to start Apache httpd.exe (I am using x64 VC11 example here)
http://www.apachelounge.com/download/VC11/
Be sure that you have installed Visual C++ Redistributable for Visual Studio 2012 : VC11 vcredist_x64/86.exe
http://www.microsoft.com/en-us/download/details...
Frequency table for a single variable
...,2,3,3,3])
print(my_series.value_counts())
3 3
2 2
1 1
dtype: int64
Notice here that the item returned is a pandas.Series
In comparison, numpy.unique returns a tuple with two items, the unique values and the counts.
vals, counts = np.unique(my_series, return_counts=True)
print(vals, co...
Problem in running .net framework 4.0 website on iis 7.0
... actually, I don't even have the CGI option. I am using windows 7, 64 bit. Trying to get ssrs to work.
– Steam
Mar 11 '14 at 5:40
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