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warning C102

Jürgen Breuer

Hello,

why differentiates the compiler in assigning a "pointer to const" an adress directly or via a function call?

void test (const uint16_t *cpui16)
{
  if (*cpui16 == 17)
    return;
}

void test1(void)
{
      uint16_t  ui16 = 9U;
      uint16_t *p    = &ui16;
const uint16_t *cp   = &ui16; //warning C102:

  test(&ui16);                //no warning
  test(p);
  test(cp);
}

And why marks the compiler a warning and the manual an error?
Compiler
warning C102: '=': different const/volatile qualifiers

Manual
*** Error C102

operator: Different const/volatile Qualifiers

I cannnot imagine a potential problem with

const uint16_t *cp   = &ui16;

Can anybody give me a hint?

Best regards
Jürgen

Parents
  • 0 in reply to Jonathan King

    Oh yes, I think I got the point.

    I know the qualifiers 'const' and 'volatile' and I tried to tell the compiler, that I don't want to change the value of the variable ui16 which the pointer cp dereferences via this pointer (as lint suggested).

    But what I really did was telling the compiler that pc dereferences a variable that would not change ever.
    And that is a difference as I see now.

    Thanks again for your kind effort although I don't see how I can satisfy lint (which suggested to declare cp as pointing to const) and the compiler (which says the variable cp dereferences isn't really const)

Reply
  • 0 in reply to Jonathan King

    Oh yes, I think I got the point.

    I know the qualifiers 'const' and 'volatile' and I tried to tell the compiler, that I don't want to change the value of the variable ui16 which the pointer cp dereferences via this pointer (as lint suggested).

    But what I really did was telling the compiler that pc dereferences a variable that would not change ever.
    And that is a difference as I see now.

    Thanks again for your kind effort although I don't see how I can satisfy lint (which suggested to declare cp as pointing to const) and the compiler (which says the variable cp dereferences isn't really const)

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