Resendin to the mailing list as plain text. On 21/03/13 17:46, Ángel González wrote: > On 21/03/13 17:08, Alexander Striffeler wrote: >> Hello >> >> I'm using g++ for a project where I have to store serialized data as >> a char*. Of course, these serialized bits are likely to contain NULL >> characters which implies that NULL-terminating strings obviously are >> a bad choice. Unfortunately, storing the information as char* is >> predetermined. This means I serialize the objects, process them as >> std::string and then store them as char*. When I try to recover the >> std::string, the behaviour is kind of strange (consider the code >> snippet below as an example): >> >> const char* hello = "hel\0lo"; >> std::string s(hello, 6); >> std::cout << "s.length() = " << s.length() << '\n'; >> std::cout << "s = \"" << s << "\"\n"; >> >> prints 'hel' on my machine running g++ v4.6.1 (which apt pretends to >> be up to date) while it prints 'hello' on a stackoverflow >> contributor's machine running version 4.4.5. (For the full question >> see stackoverflow.com/questions/15525208). >> >> Is this a known issue - and does anyone know a workaround? >> >> Any hints are very appreciated - TIA! >> >> Cheers >> Alex >> > [1] defines the constructor you are using «string (const char* s, > size_t n);» as > «Copies the first /n/ characters from the array of characters pointed > by /s/.», which is exactly what you want (ie. it doesn't stop at a > \0). Looking at the standard [2] confirms it, see page 634 of [3]: > «basic_string(const charT* s, size_type n, const Allocator& a = > Allocator()); > 7 Requires: s shall not be a null pointer and n < npos. > 8 Effects: Constructs an object of class basic_string and determines > its initial string value from the > array of charT of length n whose first element is designated by s, as > indicated in Table 66.» > > Testing with g++ 4.7.2, I see "hello". What you haven't provided is > the output of s.length() on your machine. If it's 6 I would expect the > problem be in std::cout or its underlying calls, not in std::string. > > Regards > > 1- http://www.cplusplus.com/reference/string/string/string/ > 2- http://www.open-std.org/JTC1/SC22/WG21/ > 3- http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2011/n3242.pdf
