Bug? std::string promoted to bool???

[U.Mutlu]

Why does this compile?
The 2nd par should be a bool not a std::string.
IMO the compiler should generate a warning (actually even an error) about it.

#include <string>

struct TS {};

bool func(const TS& S, const bool f, const std::string s = "")
{
//...
return f;
}

int main()
{
TS S;
func(S, "X"); // <-- HERE
return 0;
}


--
Thx
Uenal

[crim...@gmail.com]

среда, 13 мая 2015 г., 5:47:40 UTC+3 пользователь U.Mutlu написал:

> The 2nd par should be a bool not a std::string.
> IMO the compiler should generate a warning (actually even an error) about it.

...

> func(S, "X"); // <-- HERE

It is char *, not a std::string.

From docs:

Boolean conversions

Prvalues of integral, floating-point, unscoped enumeration, pointer, and pointer-to-member types can be converted to prvalues of type bool.

The value zero (for integral, floating-point, and unscoped enumeration) and the null pointer and the null pointer-to-member values become false. All other values become true.

[U.Mutlu]

But this doesn't cover this special case (char*) here, does it?
Whatever the doc says, it is IMO an extremly dangerous construct.
As such, the compiler should at least give a warning.

--
cu
Uenal