摘要： C++ Annotated Reference Manual中说“default Constructor 在需要的时候被编译器产生出来”，其关键字就是“需要的时候”，是谁需要呢？创建出来干什么事呢？class Foo {public:int val;Foo *pNext;};void foo_bar(){Foo bar;if(bar.val || bar.pnext)// do something;}在这个例子中，正确的语义是要求Foo有个default Constructor，可以将它的两个members初始化为0。但这段代码并不满足ARM中说的“在需要的时候”，其差别就在于一个是程序的需要 阅读全文

摘要： In computer science, denormal numbers or denormalized numbers (now often called subnormal numbers) fill the underflow gap around zero in floating point arithmetic: any non-zero number which is smaller than the smallest normal number is 'sub-normal'.In a normal floating point value there are 阅读全文

摘要： Basic Concepts in Kerberos Kerberos client, Kerberos server, application server In Kerberos, all authentication takes place between clients and servers. So in Kerberos terminology, a "Kerberos client"... 阅读全文

摘要： 在C++中，可以在编译时进行操纵的实体称为元数据，可以分为两个类别：类型和非类型。任何种类的元数据都可以用做模版参数。 阅读全文

摘要： 元程序(metaprogram) Metaprogramming is the writing of computer programs that write or manipulate other programs (or themselves) as their data, or that do part of the work at compile time that would otherwise be done at runtime. 所谓元编程就是说写出的程序是用来写程序或者控制程序的，或者在编译时而不是运行时做一些工作。所以各种code generation的工具、C#或者Jav 阅读全文

摘要： And they lived happily ever after So much has been written, discussed and argued about the joint life of developers and testers. It seems whenever these two groups meet, there will be more shouting th... 阅读全文

摘要： Directory Service command line utilityCreate, read, and manage Directory Service data. If invoked without any commands, dscl runs in an interactive mode, reading commands from standard input. Interactive processing is terminated by the quit command. (dscl and the GUI 'Directory utility' repl 阅读全文

摘要： A certificate is a set of data that identifies an entity. A trusted organization assigns a certificate to an individual or an entity that associates a public key with the individual. The individual or... 阅读全文

摘要： 概括来说，一个IO操作可以分为两个部分：发出请求、结果完成。如果从发出请求到结果返回，一直Block，那就是Blocking IO；如果发出请求就可以返回（结果完成不考虑），就是non-blocking IO；如果发出请求就返回，结果返回是Block在select或者poll上的，则其只能称为IO multiplexing；如果发出请求就返回，结果返回通过Call Back的方式被处理，就是AIO。文[2]中图画的不错，说的也比较清楚借来用一下。Blocking IO这个最好理解了，在Blocking IO模式下，函数调用只有在操作完成后才会返回。下图是它调用过程的图示：重点解释下上图，下面例 阅读全文

摘要： select()监测多个文件描述符，等待一个或者多个文件描述符对某些类型的IO操作（Read，Write）变成Ready状态。A file descriptor is considered ready if it is possible to perform the corresponding I/O operation without blocking. Reference1. http://daniel.haxx.se/docs/poll-vs-select.html 阅读全文