That’s not a feature of the C language but a feature of the compiler/linker and the operating system working together. When you compile such code the following happens: The compiler will put the string into a read-only data-section. The linker collects all the data in such read-only sections and puts them into a single segment. … Read more
I believe the only time “const” is appropriate is when there is a spec that you’re coding against that is more durable than the program you’re writing. For instance, if you’re implementing the HTTP protocol, having a const member for “GET” is appropriate because that will never change, and clients can certainly hard-code that into … Read more
A user in an Oracle database only has the privileges you grant. So you can create a read-only user by simply not granting any other privileges. When you create a user CREATE USER ro_user IDENTIFIED BY ro_user DEFAULT TABLESPACE users TEMPORARY TABLESPACE temp; the user doesn’t even have permission to log in to the database. … Read more
You could write your own read-only wrapper for the dictionary, e.g.: public class ReadOnlyDictionaryWrapper<TKey, TValue, TReadOnlyValue> : IReadOnlyDictionary<TKey, TReadOnlyValue> where TValue : TReadOnlyValue { private IDictionary<TKey, TValue> _dictionary; public ReadOnlyDictionaryWrapper(IDictionary<TKey, TValue> dictionary) { if (dictionary == null) throw new ArgumentNullException(“dictionary”); _dictionary = dictionary; } public bool ContainsKey(TKey key) { return _dictionary.ContainsKey(key); } public IEnumerable<TKey> Keys … Read more
That would be const. Note that this keyword means a couple of different things in different contexts.
This seems to work… function getList(): ReadonlyArray<number> { return [1, 2, 3]; } const list = getList(); list[0] = 3; // Index signature in type ‘ReadonlyArray<number>’ only permits reading. Try it in the Playground ReadonlyArray<T> is implemented like this: interface ReadonlyArray<T> { readonly [n: number]: T; // Rest of the interface removed for brevity. }
The reason is that you can only assign to readonly fields in the constructor of that class. According to the definition of readonly in the C# Reference (emphasis mine): When a field declaration includes a readonly modifier, assignments to the fields introduced by the declaration can only occur as part of the declaration or in … Read more
Well, you can use consts in attributes, since they exist as compile time. You can’t predict the value of a static readonly variable, since the .cctor could initialize it from configuration etc. In terms of usage, constants are burnt into the calling code. This means that if you recompile a library dll to change a … Read more
The compiler has made it a common, which can be merged with other compatible symbols, and which can go in bss (taking no space on disk) if it ends up with no explicitly initialized definition. Putting it in rodata would be a trade-off; you’d save memory (commit charge) at runtime, but would use more space … Read more
There is ReadOnlyCollection<T>, which is the generic version of the above. You can create one from a List<T> directly by calling list.AsReadOnly().