大约有 40,000 项符合查询结果（耗时：0.0630秒） [XML]
How to create a shared library with cmake?
...
Always specify the minimum required version of cmake
cmake_minimum_required(VERSION 3.9)
You should declare a project. cmake says it is mandatory and it will define convenient variables PROJECT_NAME, PROJECT_VERSION and PROJECT_DESCRIPTION (this latter variable necessitate cmake 3...
How do you find the row count for all your tables in Postgres
...vy activity, but is generally a good estimate:
SELECT schemaname,relname,n_live_tup
FROM pg_stat_user_tables
ORDER BY n_live_tup DESC;
That can also show you how many rows are dead, which is itself an interesting number to monitor.
The third way is to note that the system ANALYZE command, ...
Why does this async action hang?
...lock? Imagine you just have this code:
var task = dataSource.ExecuteAsync(_ => 42);
var result = task.Result;
So the first line kicks off the asynchronous work. The second line then blocks the UI thread. So when the runtime wants to run the "return result" line back on the UI thread, it can't ...
How to replace a character by a newline in Vim
...using GVim on Windows, and I need neither the :set magic (it's not in my ~/_vimrc either) or ctrl-q. Just a simple ctrl-v followed by enter creates the ^M character for me just fine.
– Chris Phillips
Sep 14 '11 at 21:02
...
Which is faster: Stack allocation or Heap allocation
...pty classes take up 1 byte of space, minimum
}
int main()
{
std::clock_t start = std::clock();
for (int i = 0; i < 100000; ++i)
empty e;
std::clock_t duration = std::clock() - start;
std::cout << "stack allocation took " << duration << " clock ticks\n";
...
Checking network connection
...
Perhaps you could use something like this:
import urllib2
def internet_on():
try:
urllib2.urlopen('http://216.58.192.142', timeout=1)
return True
except urllib2.URLError as err:
return False
Currently, 216.58.192.142 is one of the IP addresses for google.com. ...
micro:bit 微控制器教程 · App Inventor 2 中文网
...按钮也算进去，您可以在事件中加入 component 不等于 Button_Disconnect 就可以了。
micro:bit 端设置
MakeCode 编程
请到 makecode 网站，开启一个新的 micro:bit 项目并完成以下程式。
步骤1：初...
What's the difference between EscapeUriString and EscapeDataString?
...)*+,;=
For completeness, the unreserved characters are alphanumeric and -._~
Both methods escape characters that are neither reserved nor unreserved.
I disagree with the general notion that EscapeUriString is evil. I think a method that escapes only illegal characters (such as spaces) and not res...
Java and SQLite [closed]
...zentus)
Another Java - SWIG wrapper. It only works on Win32. http://rodolfo_3.tripod.com/index.html
sqlite-java-shell: 100% pure Java port of the sqlite3 commandline shell built with NestedVM. (This is not a JDBC driver).
SQLite JDBC Driver for Mysaifu JVM: SQLite JDBC Driver for Mysaifu JVM and SQL...
How can prepared statements protect from SQL injection attacks?
...very SQL injection example shows it (all examples in PHP/Mysql):
$expected_data = 1;
$query = "SELECT * FROM users where id=$expected_data";
will produce a regular query
SELECT * FROM users where id=1
while this code
$spoiled_data = "1; DROP TABLE users;"
$query = "SELECT * FROM users...