Re: warning C4238 : cast reference in void*

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Eric wrote:
Hi,

I want to pass a reference of an object as the parameter of a function.
This function takes an void*

Thats not a reference, its an address. And the trick is to cast the
receiving pointer. Note that a cast does *not* modify the casted
object. See below.


void foo(void* param)
{
...
}

int main()
{
CString szWord;

foo((void*) &szWord); //give C4238 warning : nonstandard extension
used : class rvalue used as lvalue
}

How can I solve this warning ?


void foo(void* param)
{
CString* ps = (CString*)param;
// use *ps
// or better
CString* psc = static_cast<CString*>(param);
// use *psc
}

int main()
{
CString word = "a string";
foo((void*)&word);
// or
foo(static_cast<void*>(&word));

return 0;
}

If you want foo() to take the pointer safely

void foo(void* const param) // a constant pointer to void
{
CString* ps = (CString*)param;
// param = 0; illegal
}

.

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