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Fast way to discover the row count of a table in PostgreSQL
...s. You can use a subquery with LIMIT:
SELECT count(*) FROM (SELECT 1 FROM token LIMIT 500000) t;
Postgres actually stops counting beyond the given limit, you get an exact and current count for up to n rows (500000 in the example), and n otherwise. Not nearly as fast as the estimate in pg_class, t...
What are the most widely used C++ vector/matrix math/linear algebra libraries, and their cost and be
...not safely pass-by-value
use of Eigen types as members requires special allocator customization (or you crash)
use with stl container types and possibly other templates required
special allocation customization (or you will crash)
certain compilers need special care to prevent crashes on fu...
How to get the file extension in PHP? [duplicate]
...
'Only variables should be passed by reference', the PHP Manual
– dader
Dec 20 '12 at 2:01
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How to convert a std::string to const char* or char*?
...t chance that your string implementation will need to do some extra memory allocation and/or data copying in order to prepare the NUL terminated buffer
As a further hint, if a function's parameters require the (const) char* but don't insist on getting x.size(), the function probably needs an ASCII...
Which iomanip manipulators are 'sticky'?
...:
21.3.7.9 [lib.string.io]:
template<class charT, class traits, class Allocator>
basic_ostream<charT, traits>&
operator<<(basic_ostream<charT, traits>& os,
const basic_string<charT,traits,Allocator>& str);
22.2.2.2.2 [lib.facet.num.p...
How do you loop in a Windows batch file?
...do I use for loop to get inside a previously set variable? I tried for /F "tokens=2 delims=," %%i in ( %a% ) do ( ….. but this doesn't work. It fails saying " ( was unexpected at this time"
– Shivani
Jan 3 at 10:57
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Safely remove migration In Laravel
...
I accidentally created a migration with a bad name (command: php artisan migrate:make). I did not run (php artisan migrate) the migration, so I decided to remove it.
My steps:
Manually delete the migration file under app/database/migrations/my_migration_file_name.php
Reset the compos...
PHP屏蔽警告错误，PHP不输出警告错误 - 更多技术 - 清泛网 - 专注C/C++及内核技术
PHP屏蔽警告错误，PHP不输出警告错误诸如下面这些错误的提示：Warning: file_get_contents( usr local tads htdocs XXXXXX src cache countLoginnum.txt) [function.file-get...诸如下面这些错误的提示：
Warning: file_get_contents(/usr/local/tads/htdocs/XXXXXX/src/cach...
PHP开发利器EPP4发布 基于Eclipse核心 - IT产品资讯 - 清泛网 - 专注C/C++及内核技术
PHP开发利器EPP4发布 基于Eclipse核心EclipsePHP Studio 简体中文版介绍 - EPPEclipsePHP Studio 简称 EPP ，EPP 使用的 Eclipse 核心编译而来。针对PHP开发者提供的
EclipsePHP Studio 简体中文版介绍 - EPP
EclipsePHP Studio 简称 “EPP ”，EP...
How to “return an object” in C++?
...hat, you'd probably want to do the out parameter. It avoids dynamic memory allocation, which is safer and generally faster. It does require you have some way to construct the object prior to calling the function, which doesn't always make sense for all objects.
If you want to use dynamic allocation...