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Use of 'const' for function parameters
...o allows the compiler to make certain performance decisions.
*: Unless it casts away the const-ness, but that's another post.
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Abstract class in Java
...
If we wish to access a member specific to a particular subclass, we must cast down to that subclass first:
// Say ImplementingClass also contains uniqueMethod()
// To access it, we use a cast to tell the runtime which type the object is
AbstractClass b = new ImplementingClass();
((ImplementingCla...
What are some uses of template template parameters?
...ALUE> class interface {
void do_something(VALUE v) {
static_cast<DERIVED*>(this)->do_something(v);
}
};
template <typename VALUE> class derived : public interface<derived, VALUE> {
void do_something(VALUE v) { ... }
};
typedef interface<derived<int...
How can I add to List
...
You can't (without unsafe casts). You can only read from them.
The problem is that you don't know what exactly the list is a list of. It could be a list of any subclass of Number, so when you try to put an element into it, you don't know that the ele...
How do I modify fields inside the new PostgreSQL JSON datatype?
...nb manipulation functionality within PostgreSQL itself (but none for json; casts are required to manipulate json values).
Merging 2 (or more) JSON objects (or concatenating arrays):
SELECT jsonb '{"a":1}' || jsonb '{"b":2}', -- will yield jsonb '{"a":1,"b":2}'
jsonb '["a",1]' || jsonb '["b",2...
How do I safely pass objects, especially STL objects, to and from a DLL?
...iginal_type get() const
{
original_type result;
result = static_cast<original_type>(*data);
return result;
}
void set_from(const original_type& value)
{
data = reinterpret_cast<safe_type*>(pod_helpers::pod_malloc(sizeof(safe_type))); //note the pod_malloc c...
Why is it slower to iterate over a small string than a small list?
...IIObject *)(op))->state.kind) is (I think) an indirection and a C-level cast);
#define PyUnicode_DATA(op) \
(assert(PyUnicode_Check(op)), \
PyUnicode_IS_COMPACT(op) ? _PyUnicode_COMPACT_DATA(op) : \
_PyUnicode_NONCOMPACT_DATA(op))
(which is also boring for similar reasons, assu...
Exporting functions from a DLL with dllexport
... ::LoadLibrary(T"opengl_plugin.dll");
m_pfnGetEngineVersion = reinterpret_cast<fnGetEngineVersion *>(
::GetProcAddress(m_hDLL, "getEngineVersion")
);
m_pfnRegisterPlugin = reinterpret_cast<fnRegisterPlugin *>(
::GetProcAddress(m_hDLL, "registerPlugin")
);
...
Foreign Key to multiple tables
...
ID int primary key,
Name varchar(50) NOT NULL,
PartyTypeId as cast(2 as tinyint) persisted,
foreign key (ID, PartyTypeId) references Party(PartyId, PartyTypeID)
)
CREATE TABLE dbo.[User]
(
ID int primary key,
Name varchar(50) NOT NULL,
PartyTypeId as cast(1 as tinyint...
Why is String.chars() a stream of ints in Java 8?
... know that the IntStream contains char values represented as ints and that casting must be done at the proper place. This is doubly confusing because there are overloaded API calls like PrintStream.print(char) and PrintStream.print(int) that differ markedly in their behavior. An additional point of ...