大约有 40,000 项符合查询结果（耗时：0.0692秒） [XML]
Easily measure elapsed time
...ompile time you can parametrize the timing type (milliseconds, nanoseconds etc).
Thanks to the review by Loki Astari and the suggestion to use variadic templates.
This is why the forwarded function call.
#include <iostream>
#include <chrono>
template<typename TimeT = std::chrono::...
Rails 4 multiple image or file upload using carrierwave
...tiple_image_upload_carrierwave
In gem file
gem 'carrierwave'
bundle install
rails generate uploader Avatar
Create post scaffold
rails generate scaffold post title:string
Create post_attachment scaffold
rails generate scaffold post_attachment post_id:integer avatar:string
rake db:migrate
...
Bring element to front using CSS
...
I don't really remember the circumstances of my question clearly, but my problem was, that I understood what z-index does, but still it did not work. What I have learned from this answer is, that with z-index you have to take into cons...
Abort makefile if variable not set
... an auxiliary function for that:
# Check that given variables are set and all have non-empty values,
# die with an error otherwise.
#
# Params:
# 1. Variable name(s) to test.
# 2. (optional) Error message to print.
check_defined = \
$(strip $(foreach 1,$1, \
$(call __check_defined,$...
Why #define TRUE (1==1) in a C boolean macro instead of simply as 1?
...type (and resolve to true and false) if the compiler supports it. (specifically, C++)
However, it would be better to check whether C++ is in use (via the __cplusplus macro) and actually use true and false.
In a C compiler, this is equivalent to 0 and 1.
(note that removing the parentheses will bre...
Which characters need to be escaped when using Bash?
...h but also bash.
1. Put the whole string in single quotes
This works for all chars except single quote itself. To escape the single quote, close the quoting before it, insert the single quote, and re-open the quoting.
'I'\''m a s@fe $tring which ends in newline
'
sed command: sed -e "s/'/'\\\\'...
Troubleshooting “Illegal mix of collations” error in mysql
...
This is generally caused by comparing two strings of incompatible collation or by attempting to select data of different collation into a combined column.
The clause COLLATE allows you to specify the collation used in the query.
For exa...
Ruby replace string with captured regex pattern
...d answer first without reading the entirety of answers. That seems to generally be the most efficient means of fixing a problem. Give Vicky a break! :)
– Josh M.
Jan 31 '14 at 3:43
...
Extracting text OpenCV
...
For some cards the bounding box does not enclose all of the text, such as half a letter getting cut off. Such as this card: i.imgur.com/tX3XrwH.jpg How can I extend every bounding bounding boxes height and width by n? Thanks for the solution it works great!
...
Where are $_SESSION variables stored?
...ariable storage is determined by PHP's session.save_path configuration. Usually this is /tmp on a Linux/Unix system. Use the phpinfo() function to view your particular settings if not 100% sure by creating a file with this content in the DocumentRoot of your domain:
<?php
phpinfo();
?>
...