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std::shared_ptr thread safety explained
...pace std;
struct A
{
int a;
A(int a) : a(a) {}
};
int main(int argc, char **argv)
{
shared_ptr<A> a(new A(1));
shared_ptr<A> b(a), c(a), d(a);
cout << "a: " << a->a << "\tb: " << b->a
<< "\tc: " << c->a << "\td: " <&...
How do you debug MySQL stored procedures?
...E debug_msg(enabled INTEGER, msg VARCHAR(255))
BEGIN
IF enabled THEN
select concat('** ', msg) AS '** DEBUG:';
END IF;
END $$
CREATE PROCEDURE test_procedure(arg1 INTEGER, arg2 INTEGER)
BEGIN
SET @enabled = TRUE;
call debug_msg(@enabled, 'my first debug message');
call debug_msg(@ena...
Postgres NOT in array
...
SELECT COUNT(*) FROM "messages" WHERE NOT (3 = ANY (recipient_ids))
You can always negate WHERE (condition) with WHERE NOT (condition)
share
...
Errors: “INSERT EXEC statement cannot be nested.” and “Cannot use the ROLLBACK statement within an I
...our stored procedure data into it
EXAMPLE:
INSERT INTO #YOUR_TEMP_TABLE
SELECT * FROM OPENROWSET ('SQLOLEDB','Server=(local);TRUSTED_CONNECTION=YES;','set fmtonly off EXEC [ServerName].dbo.[StoredProcedureName] 1,2,3')
Note: You MUST use 'set fmtonly off', AND you CANNOT add dynamic sql to this...
How to select rows with one or more nulls from a pandas DataFrame without listing columns explicitly
... 0.0 NaN 0.0
3 0.0 1.0 2.0 3.0
4 NaN 0.0 NaN NaN
If you want to select the rows that have two or more columns with null value, you run the following:
>>> qty_of_nuls = 2
>>> df.iloc[df[(df.isnull().sum(axis=1) >=qty_of_nuls)].index]
0 1 2 3
1 0.0 NaN 0...
Input widths on Bootstrap 3
Update again: I am closing this question by selecting the top answer to keep people from adding answers without really understanding the question. In reality there is no way to do it with the build in functionality without using grid or adding extra css. Grids do not work well if you are dealing wi...
What does $_ mean in PowerShell?
...dItem | Add-Member -Type NoteProperty -Name Bar -Value $_.Name -PassThru | Select Bar ... Well, it can work if you have a $_ in the scope where you're executing that pipeline. But that's very different from what you usually mean when trying to write something like that.
– Joey
...
Default implementation for Object.GetHashCode()
...sually more interested in whether a string containing the same sequence of characters has already been added. That's why string overrides GetHashCode. On the other hand, suppose you want to keep a count of how many times various controls process Paint events. You could use a Dictionary<Object,...
What is the point of the diamond operator () in Java 7?
...de by saving repeated type arguments. In practice, it's just two confusing chars more giving you nothing. Why?
No sane programmer uses raw types in new code. So the compiler could simply assume that by writing no type arguments you want it to infer them.
The diamond operator provides no type infor...
How to alias a table in Laravel Eloquent queries (or using Query Builder)?
...AS. Try
$users = DB::table('really_long_table_name AS t')
->select('t.id AS uid')
->get();
Let's see it in action with an awesome tinker tool
$ php artisan tinker
[1] > Schema::create('really_long_table_name', function($table) {$table->increments('id');});
// N...