STL string class

[mike7411]

When you use she STL string class and the c_str() function, how does
the memory returned by c_str() get allocated and destroyed?

Thank you.

 

[Mark P]

When you use she STL string class and the c_str() function, how does
the memory returned by c_str() get allocated and destroyed?

Thank you.

The memory is controlled by the string object-- after the string is
destructed you must not access the memory returned by c_str().

 

[Ivan Vecerina]

: (e-mail address removed) wrote:
: > When you use she STL string class and the c_str() function, how does
: > the memory returned by c_str() get allocated and destroyed?
: >
: > Thank you.
: >
:
: The memory is controlled by the string object
Yep.

: after the string is destructed
: you must not access the memory returned by c_str().

Not only destruction, but any operation that modifies
the string may invalidate the memory that was returned
by c_str().
I.e.:
std::string s = "Hello";
char const* p = s.c_str();
std::cout << p << std::endl; //ok
s.append('.');
std::cout << p << std::endl; // UNDEFINED BEHAVIOR


hth -Ivan

 

[James Kanze]

"Mark P" <[email protected]> wrote in message

news:[email protected]...: (e-mail address removed) wrote:

: > When you use she STL string class and the c_str() function, how does
: > the memory returned by c_str() get allocated and destroyed?

: The memory is controlled by the string object
Yep.

: after the string is destructed
: you must not access the memory returned by c_str().

Not only destruction, but any operation that modifies

Any operation which permits modification, in fact. Calling [],
at(), begin() or end() on a non-const string, or through a
non-const reference to the string, may also invalidate the
pointer.