literal (C++)
A variable (data member) marked as literal in a /clr compilation is the native equivalent of a static const variable.
Remarks
A data member marked as literal must be initialized when declared and the value must be a constant integral, enum, or string type. Conversion from the type of the initialization expression to the type of the static const data-member must not require a user-defined conversion.
No memory is allocated for the literal field at runtime; the compiler only inserts its value in the metadata for the class.
A variable marked static const will not be available in metadata to other compilers.
For more information, see Static (C++) and const (C++).
literal is a context-sensitive keyword. See Context-Sensitive Keywords for more information.
Example
This example shows that a literal variable implies static.
// mcppv2_literal.cpp
// compile with: /clr
ref struct X {
literal int i = 4;
};
int main() {
int value = X::i;
}
The following sample shows the affect of literal in metadata:
// mcppv2_literal2.cpp
// compile with: /clr /LD
public ref struct A {
literal int lit = 0;
static const int sc = 1;
};
Notice the difference in the metadata for sc and lit: the modopt directive is applied to sc, meaning it can be ignored by other compilers.
.field public static int32 modopt([mscorlib]System.Runtime.CompilerServices.IsConst) sc = int32(0x0000000A)
.field public static literal int32 lit = int32(0x0000000A)
The following sample, authored in C#, references the metadata created in the previous sample and shows the affect of literal and static const variables:
// mcppv2_literal3.cs
// compile with: /reference:mcppv2_literal2.dll
// A C# program
class B {
public static void Main() {
// OK
System.Console.WriteLine(A.lit);
System.Console.WriteLine(A.sc);
// C# does not enforce C++ const
A.sc = 9;
System.Console.WriteLine(A.sc);
// C# enforces const for a literal
A.lit = 9; // CS0131
// you can assign a C++ literal variable to a C# const variable
const int i = A.lit;
System.Console.WriteLine(i);
// but you cannot assign a C++ static const variable
// to a C# const variable
const int j = A.sc; // CS0133
System.Console.WriteLine(j);
}
}