Invalid use of pointer in notnull_tests.cpp TEST_CASE("TestNotNullostream") #737
Description
Detected with the help of valgrind which shows strlen accessing invalid memory. In the excerpt below, p is a pointer to a single char, but the ostream::operator()<< does not know this and assume it's a pointer to char, and will end up calling strlen via _Traits::length(__s)). Turns out there is a null terminator in memory, 29 bytes after the 'c', so no crash and the test passes. I solved this by casting to void * p and &v.
TEST_CASE("TestNotNullostream")
{
...
ostream_helper<char>('c');
...
}
void ostream_helper(T v)
{
not_null<T*> p(&v);
{
std::ostringstream os;
std::ostringstream ref;
os << p; ///// HEREHERE
ref << &v; ///// HEREHERE
CHECK(os.str() == ref.str());
}
}
For reference here is the code to operator<<
template<class _Traits>
inline basic_ostream<char, _Traits>&
operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
{
if (!__s)
__out.setstate(ios_base::badbit);
else
__ostream_insert(__out, __s,
static_cast<streamsize>(_Traits::length(__s))); ///// HEREHERE
return __out;
}