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Defining a function with multiple implicit arguments in Scala
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They must all go in one parameter list, and this list must be the last one.
def myfun(arg:String)(implicit p1: String, p2:Int)={}
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What is a “callback” in C and how are they implemented?
...y're implemented using function pointers. Here's an example:
void populate_array(int *array, size_t arraySize, int (*getNextValue)(void))
{
for (size_t i=0; i<arraySize; i++)
array[i] = getNextValue();
}
int getNextRandomValue(void)
{
return rand();
}
int main(void)
{
int m...
Is there a max array length limit in C++?
...se memory is full. For example, a vector<int> of a given size n typically takes multiple times as much memory as an array of type vector<char> (minus a small constant value), since int is usually bigger than char. Therefore, a vector<char> may contain more items than a vector<in...
Run PostgreSQL queries from the command line
... assuming that you have not finished entering your query. This can lead to all kinds of confusion. For example, if you re-enter the same query you will have most likely create a syntax error.
As an experiment, try typing any garble you want at the psql prompt then hit enter. psql will silently prov...
Android - Package Name convention
...ou consider each period ('.') in the application name as a path separator, all applications from a publisher would sit together in the path hierarchy.
So, for instance, packages from Adobe would be of the form:
com.adobe.reader (Adobe Reader)
com.adobe.photoshop (Adobe Photoshop)
com.adobe.ideas ...
Converting NSString to NSDate (and back again)
...String = @"01-02-2010";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd-MM-yyyy"];
NSDate *dateFromString = [dateFormatter dateFromString:dateString];
NSDate convert to NSString:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[d...
Why is a C++ Vector called a Vector?
The question's pretty self-explanatory really. I know vaguely about vectors in maths, but I don't really see the link to C++ vectors.
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How do I terminate a thread in C++11?
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You could call std::terminate() from any thread and the thread you're referring to will forcefully end.
You could arrange for ~thread() to be executed on the object of the target thread, without a intervening join() nor detach() on that...
How do I clone a Django model instance object and save it to the database?
...imary key of your object and run save().
obj = Foo.objects.get(pk=<some_existing_pk>)
obj.pk = None
obj.save()
If you want auto-generated key, set the new key to None.
More on UPDATE/INSERT here.
Official docs on copying model instances: https://docs.djangoproject.com/en/2.2/topics/db/que...
Creating hard and soft links using PowerShell
Can PowerShell 1.0 create hard and soft links analogous to the Unix variety?
11 Answers
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