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In a 2008 post on his site, Herb Sutter states the following:
There is an active proposal to tighten this up further in C++0x and require null-termination and possibly ban copy-on-write implementations, for concurrency-related reasons. Here’s the paper: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2008/n2534.html . I think that one or both of the proposals in this paper is likely to be adopted, but we’ll see at the next meeting or two.
I know that C++11 now guarantees that the std::string contents get stored contiguously, but did they adopt the above in the final draft?
Will it now be safe to use something like &str[0]?
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Actually, as of C++11 std::string is guaranteed to be null terminated. Specifically, s[s. size()] will always be '\0' .
In C the strings are basically array of characters. In C++ the std::string is an advancement of that array. There are some additional features with the traditional character array. The null terminated strings are basically a sequence of characters, and the last element is one null character (denoted by '\0').
Thus, NULL isn't a valid value for a std::string. They *can't* really be NULL. The relevant overloads for std::string are to compare a std::string to a std::string, a char* to a std::string, or a std::string to a char*.
It is known as the null character, or NUL, and standard C strings are null-terminated. This terminator signals code that processes strings - standard libraries but also your own code - where the end of a string is.
Yes. Per the C++0x FDIS 21.4.7.1/1, std::basic_string::c_str() must return
a pointer
psuch thatp + i == &operator[](i)for eachiin[0,size()].
This means that given a string s, the pointer returned by s.c_str() must be the same as the address of the initial character in the string (&s[0]).
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