__gc and __nogc ???

[Chris]

Hi,

if have a __gc class with a datamember of type : a pointer to a DateTime,
but I get a compiler error :

__gc class Employee
{
public:
DateTime * m_hiringDate; ==> error : cannot declare interior __gc
pointer or
reference as a member of 'class'

Employee(DateTime * hiringDate) {
m_hiringDate = hiringDate;
}
};

so, I declare the pointer and Ctor a follows :

DateTime __nogc * m_hiringDate; ==> OK

Employee(DateTime __nogc * hiringDate) {
m_hiringDate = hiringDate;
}

but then do I get an error when allocating a new Employee

Employee *emp = new Employee(new DateTime(2001,1,1));

==> error : cannot dynamically allocate a value type object with managed
members
on C++ (nogc) heap

How can I make it work ?
What is the proper way do deal with this situation ?

thnx
Chris

 

[Ben Schwehn]

__gc class Employee

{
public:
DateTime * m_hiringDate; ==> error : cannot declare interior __gc

Chris,
you could use

DateTime m_hiringDate;

instead.

http://msdn.microsoft.com/library/d...vcmxspec/html/vcmanagedextensionsspec_7_4.asp

"Note that although variables with type "__gc pointer to __value class"
point to a whole __value class, they are nevertheless considered
interior pointers; any __value class on the runtime heap must be
embedded within a __gc object."

hth

 

[Tomas Restrepo \(MVP\)]

Chris,

if have a __gc class with a datamember of type : a pointer to a DateTime,
but I get a compiler error :

__gc class Employee
{
public:
DateTime * m_hiringDate; ==> error : cannot declare interior __gc
pointer or
reference as a member of 'class'

Employee(DateTime * hiringDate) {
m_hiringDate = hiringDate;
}
};

DateTime is a value type, why are you dealing with it with pointers? Just
store the value directly:

__gc class Employee
{
public:
DateTime m_hiringDate;

Employee(DateTime hiringDate) {
m_hiringDate = hiringDate;
}
};