Declaring a const BYTE * in c++

Question

I am currently trying to make a call to this function call. Here's the declaration:

const void* WINAPI CertCreateContext(
  __in      DWORD dwContextType,
  __in      DWORD dwEncodingType,
  __in      const BYTE *pbEncoded,
  __in      DWORD cbEncoded,
  __in      DWORD dwFlags,
  __in_opt  PCERT_CREATE_CONTEXT_PARA pCreatePara
);

As you can see, the third input param calls for a const BYTE * which represents the encoded certificate you are trying to create. How do I define such a variable in c++?

Answer 1

You only need to declare a BYTE*, the compiler will automatically cast's non-consts to consts.

Answer 2

You don't need to. The function parameter is a pointer to a const BYTE, which means the function will not change the byte it points to. A simple example:

void f( const BYTE * p ) {
    // stuff
}

BYTE b = 42;
BYTE a[] = { 1, 2, 3 };

f( & b );
f( a );

You will of course need to #include the header that declares the type BYTE.

Answer 3

According to the documentation:

pbEncoded is a pointer to a buffer that contains the existing encoded context content to be copied.

Answer 4

Pass in a regular pointer to BYTE. The const there indicates that the pointed-to object will not be modified inside the function.