[cfe-dev] const stripped in typedefs for parameters of primitive type?

David Blaikie dblaikie at gmail.com
Sun Aug 24 14:42:10 PDT 2014

On Aug 24, 2014 1:06 PM, "Jacob Carlborg" <doob at me.com> wrote:
> On 2014-08-23 22:42, David Blaikie wrote:
>> This is how C behaves - the const has no effect on the function type
> So a typedef strips const for parameters of a value type? But otherwise
it's not stripped, seems odd.

Try writing these two functions in one file:

  void func(int) {}
  void func(const int) {}

And it won't compile (but if you add * yo each parameter it will) because
the functions have the same type.

This is because the const has no effect on the caller - in either case the
caller can pass a const or non-const int because it will be copied (not
modified) to the caller.

Whereas if there's indirection it matters greatly yo the caller whether tit
gave a pointer through which data could be modified or not.

But this const doesn't affect the caller (so these are the same function:

  void func(int *)
  void func(int * const)

Because the pointer (which is copied) is constant, but what it points to is
still non-const in both cases.

> --
> /Jacob Carlborg
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