libc++ defines getline(istream, string) in <istream> instead of <string> #25606
Description
| Bugzilla Link | 25232 |
| Version | unspecified |
| OS | All |
| CC | @mclow |
Extended Description
This doesn't link:
$ cat test.cc
#include <iosfwd>
#include <string>
std::string f(std::istream& is) {
std::string s;
std::getline(is, s);
return s;
}
$ clang++ -shared test.cc -o libfoo.so
Undefined symbols for architecture x86_64:
"std::__1::basic_istream<char, std::__1::char_traits<char> >& std::__1::getline<char, std::__1::char_traits<char>, std::__1::allocator<char> >(std::__1::basic_istream<char, std::__1::char_traits<char> >&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&)", referenced from:
f(std::__1::basic_istream<char, std::__1::char_traits<char> >&) in test-935a1a.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
http://en.cppreference.com/w/cpp/string/basic_string/getline says that this function should be in <string>. In libc++, it's declared in <string> but defined in <istream>. If I add an #include <istream> to the file above, it links fine.
Bug 10390 added the declarations to <string>, but it seems that the definition should be there too?
(I kind of feel that I filed this before and that someone explained to me why this things are arguably correct as they are now, but I can't find anything like that.)