CODEWITHSUNDEEP
c++castingprogram-entry-point
Nan Hua
Nan Hua

Reputation: 3694

Convert type "char**" to "const char**"

The following code can't compile:

  char** s;
  const char** s2 = s;

I know the followings can work but I think there should be some better legitimate way to do it?

  long long x = reinterpret_cast<long long>(s);
  s2 = reinterpret_cast<const char**>(x);

The background of this question is, I want to use two libraries which have functions handling argc/argv with different signatures:

void Init1(int argc, char** argv);
void Init2(int argc, const char** argv);

Then what's the best way to define my signature of main to call both of those two functions?

Upvotes: 2

Views: 2570

Answers (1)

Jack
Jack

Reputation: 133609

In C++ you can add or remove const-ness through const_cast, eg:

char** s;
const char** t = const_cast<const char**>(s);

Since you are dealing with argv it should be quite safe to add const-ness to them as long as the Init2 doesn't try to alter anything, and it shouldn't since its argument is const char**.

Mind that attepting to modify the value of a variable that was const after removing the cv qualifier leads to undefined behavior.

Upvotes: 3

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