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How do I print a double value with full precision using cout?
...int out the binary bits (or hex nybbles).
One way of doing that is using a union to type-pun the double to a integer and then printing the integer, since integers do not suffer from truncation or round-off issues. (Type punning like this is not supported by the C++ standard, but it is supported in C...
phpmyadmin logs out after 1440 secs
In my local development Ubuntu box I use MySQL and phpmyadmin to work with the database.
24 Answers
...
通过FastCGI Cache实现服务降级 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...图中的目标就会发现：它没有实现全局激活缓存的功能。如何实现呢？最简单的方法就是通过单位时间内出错次数的多少来判断系统健康以否，设置相应的阈值，一旦超过限制就全局激活缓存，通过Lua我们可以实现一个定制版：...
Difference between “read commited” and “repeatable read”
...nd consider you have a simple task like the following:
BEGIN TRANSACTION;
SELECT * FROM T;
WAITFOR DELAY '00:01:00'
SELECT * FROM T;
COMMIT;
That is a simple task that issue two reads from table T, with a delay of 1 minute between them.
under READ COMMITTED, the second SELECT may return any da...
SQL - find records from one table which don't exist in another
...shortest statement, and may be quickest if your phone book is very short:
SELECT *
FROM Call
WHERE phone_number NOT IN (SELECT phone_number FROM Phone_book)
alternatively (thanks to Alterlife)
SELECT *
FROM Call
WHERE NOT EXISTS
(SELECT *
FROM Phone_book
WHERE Phone_book.phon...
Socket send函数和recv函数详解以及利用select()函数来进行指定时间的阻塞 ...
...有情况下，发送开始调用是局部的：无论其它进程的状态如何，它立刻返回。如果这个调用使得一些系统资源用完，那么它将失败并返回 一个错误代码。高质量的MPI实现应保证这种情况只在“病态”时发生。即，一个MPI实现将...
CMake使用教程 - C/C++ - 清泛网 - 专注C/C++及内核技术
...中找到这个手册对应的代码。
1、Step1。
（如果不知道如何使用cmake，以及如何使用编译产生的Turorial.exe，可先看下前面“CMake使用步骤”的说明，它以Step4为例详细介绍了使用过程，Step1的配置可能不够完全，比如无法运行make...
Selecting only first-level elements in jquery
How can I select the link elements of only the parent <ul> from a list like this?
10 Answers
...
Fetch the row which has the Max value for a column
... multiple rows for the userid where the maximum date is on multiple rows.
select userid,
my_date,
...
from
(
select userid,
my_date,
...
max(my_date) over (partition by userid) max_my_date
from users
)
where my_date = max_my_date
"Analytic functions rock"
Edi...
Oracle: If Table Exists
...
declare
c int;
begin
select count(*) into c from user_tables where table_name = upper('table_name');
if c = 1 then
execute immediate 'drop table table_name';
end if;
end;
That's for checking whether a table in the current schema exi...