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Why is address zero used for the null pointer?
...
@GMan - You are correct. On early CPUs, memory address zero was special and had hardware protection against access from running software (in some cases it was the start of the reset vector, and modifying it could prevent the CPU from resetting or starting up)...
Debug Error \"pure virtual function call\" 原因解析 - 更多技术 - 清泛...
...函数中抛出异常，不然，我们不得不面对以下两个严重的问题：
二次异常导致程序退出;
遗留下来的未完全销毁的对象与未完成的工作导致的后续问题
pure virtual function call就是这种情况。
但是理想与现实总是有差距的，...
Why does my application spend 24% of its life doing a null check?
...uting instructions, it is accessing memory. The execution core of a modern CPU is many times faster than the memory bus. A problem related to distance, the further an electrical signal has to travel, the harder it gets to get that signal delivered to the other end of the wire without it being corrup...
Virtual functions and performance - C++
...curious, so I went ahead and ran some timings on the 3GHz in-order PowerPC CPU we work with. The test I ran was to make a simple 4d vector class with get/set functions
class TestVec
{
float x,y,z,w;
public:
float GetX() { return x; }
float SetX(float to) { return x=to; } // and so on...
LinkedIn联合创始人：初创企业早期别花钱买用户 - 资讯 - 清泛网 - 专注C/C...
...程是如何运作的”的数据以及信息，虽然他们设计的招聘问题很有趣，但事实上经过专业训练的HR都不会提出(Google报告里)这些问题，这些问题的设计者，要是很熟悉HR问的问题但又不拘泥于传统观念的人，他也必须是要理解招聘...
How can I check if a Perl array contains a particular value?
...grep, hash...
any: 0 wallclock secs ( 0.67 usr + 0.00 sys = 0.67 CPU) @ 149253.73/s (n=100000)
first: 1 wallclock secs ( 0.63 usr + 0.01 sys = 0.64 CPU) @ 156250.00/s (n=100000)
grep: 42 wallclock secs (41.95 usr + 0.08 sys = 42.03 CPU) @ 2379.25/s (n=100000)
hash: 0 ...
How do I get current date/time on the Windows command line in a suitable format for usage in a file/
....
@echo off
setlocal
del /q /f %temp%\timestampfile_*
Logman.exe stop ts-CPU 1>nul 2>&1
Logman.exe delete ts-CPU 1>nul 2>&1
Logman.exe create counter ts-CPU -sc 2 -v mmddhhmm -max 250 -c "\Processor(_Total)\%% Processor Time" -o %temp%\timestampfile_ >nul
Logman.exe start ...
Nginx缓存解决方案：SRCache - 更多技术 - 清泛网 - 专注C/C++及内核技术
...多的时候，冗余的浪费将非常严重，此外还有数据一致性问题，所以它只是一个粗线条的解决方案。
对此类问题而言，SRCache是一个细粒度的解决方案。其工作原理大致如下：
SRCache工作原理
当问题比较简单的时候，通常SRC...
How to see top processes sorted by actual memory usage?
... Yes
N PID Yes
P %CPU Yes
T TIME+ Yes
Or alternatively: hit Shift + f , then choose the display to order by memory usage by hitting key n then press Enter. You will see active pr...
实现一个简单的服务端推方案 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...时性较差。虽然可以通过加快轮询频率的方式来缓解这个问题，但相应付出的代价也不小：一来会使负载居高不下，二来也会让带宽捉襟见肘。
再来说说Long Polling，如果使用传统的LAMP技术去实现的话，大致如下所示：
Long Pol...