c++ - Why doesn't std::string provide implicit conversion to char*?

Question

std::string provides const char* c_str ( ) const which:

Get C string equivalent

Generates a null-terminated sequence of characters (c-string) with the same content as the string object and returns it as a pointer to an array of characters.

A terminating null character is automatically appended.

The returned array points to an internal location with the required storage space for this sequence of characters plus its terminating null-character, but the values in this array should not be modified in the program and are only granted to remain unchanged until the next call to a non-constant member function of the string object.

Why don't they just define operator const char*() const {return c_str();}?

Answer 1

From the C++ Programming Language 20.3.7 (emphasis mine):

Conversion to a C-style string could have been provided by an operator const char*() rather than c_str(). This would have provided the convenience of an implicit conversion at the cost of surprises in cases in which such a conversion was unexpected.