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907c1196a7
Libc++ is used as a system library on macOS and iOS (amongst others). In order for users to be able to compile a binary that is intended to be deployed to an older version of the platform, clang provides the availability attribute <https://clang.llvm.org/docs/AttributeReference.html#availability>_ that can be placed on declarations to describe the lifecycle of a symbol in the library. See docs/DesignDocs/AvailabilityMarkup.rst for more information. Differential Revision: https://reviews.llvm.org/D31739 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@302172 91177308-0d34-0410-b5e6-96231b3b80d8
79 lines
1.9 KiB
C++
79 lines
1.9 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// XFAIL: with_system_cxx_lib=macosx10.7
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// XFAIL: with_system_cxx_lib=macosx10.8
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// <istream>
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// basic_istream<charT,traits>& seekg(pos_type pos);
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#include <istream>
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#include <cassert>
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template <class CharT>
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struct testbuf
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: public std::basic_streambuf<CharT>
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{
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typedef std::basic_string<CharT> string_type;
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typedef std::basic_streambuf<CharT> base;
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private:
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string_type str_;
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public:
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testbuf() {}
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testbuf(const string_type& str)
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: str_(str)
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{
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base::setg(const_cast<CharT*>(str_.data()),
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const_cast<CharT*>(str_.data()),
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const_cast<CharT*>(str_.data()) + str_.size());
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}
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CharT* eback() const {return base::eback();}
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CharT* gptr() const {return base::gptr();}
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CharT* egptr() const {return base::egptr();}
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protected:
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typename base::pos_type seekpos(typename base::pos_type sp,
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std::ios_base::openmode which)
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{
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assert(which == std::ios_base::in);
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return sp;
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}
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};
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int main()
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{
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{
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testbuf<char> sb(" 123456789");
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std::istream is(&sb);
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is.seekg(5);
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assert(is.good());
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is.seekg(-1);
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assert(is.fail());
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}
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{
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testbuf<wchar_t> sb(L" 123456789");
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std::wistream is(&sb);
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is.seekg(5);
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assert(is.good());
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is.seekg(-1);
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assert(is.fail());
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}
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{
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testbuf<char> sb(" 123456789");
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std::istream is(&sb);
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is.setstate(std::ios_base::eofbit);
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assert(is.eof());
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is.seekg(5);
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assert(is.good());
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assert(!is.eof());
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}
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}
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