C++ : Meaning of const char*const*

c++ pointers function-prototypes function-parameter
vigs1990 picture vigs1990 · Apr 5, 2012 · Viewed 15.9k times · Source

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

Samuel Harmer picture Samuel Harmer · Apr 5, 2012

From the C++ Super-FAQ:

Read the pointer declarations right-to-left.

  • const X* p means "p points to an X that is const": the X object can't be changed via p.
  • X* const p means "p is a const pointer to an X that is non-const": you can't change the pointer p itself, but you can change the X object via p.
  • const X* const p means "p is a const pointer to an X that is const": you can't change the pointer p itself, nor can you change the X object via p.

And, oh yea, did I mention to read your pointer declarations right-to-left?

const char * const * is the same as char const * const *: a (non-const) pointer to a const pointer to a const char.

const char * is the same as char const *: a (non-const) pointer to a const char.

const char * * is the same as char const * *: a (non-const) pointer to a (non-const) pointer to a const char.

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