C++ : Meaning of const char*const*

Question

In one of the C++ programs, I saw a function prototype : int Classifier::command(int argc, const char*const* argv)

What does const char*const* argv mean? Is it the same as const char* argv[]? Does const char** argv also mean the same?

Answer 1

No, it's not the same as const char *argv[]. The const prohibits modifications of the dereferenced value at the particular level of dereferencing:

**argv = x; // not allowed because of the first const
*argv = y; // not allowed because of the second const
argv = z; // allowed because no const appears right next to the argv identifier