Why does constructing std::string(0) not emit a compiler warning?
c++, compiler-construction, compiler-warnings, stl
Solution
`0` is an integer constant expression with value 0, so it is a null pointer constant. Using a 0-valued constant as a null pointer is not a cast.
C++11 introduces `nullptr` (and `nullptr_t`), but the treatment of `0` as a null pointer is unlikely to change in the near future as large amounts of code depends on it.
Problem
Say I have this piece of code. ``` #include <string> int main() { std::string(0); return 0; } ``` Writing `std::string(0)` results in `std::basic_string<char>::basic_string(const char*)` being called, with `0` as the argument to this constructor, which tries to treat the argument as a pointer to a C-string. Running this code obviously results in a `std::logic_error` being thrown. But my question is this : why both GCC and MSVC 8.0 don't emit any warnings? I'd expect to see something along the lines of "Making pointer from an integer without a cast".