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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// <fstream>
// int_type pbackfail(int_type c = traits::eof());
#include <fstream>
#include <cassert>
#include "test_macros.h"
template <class CharT>
struct test_buf
: public std::basic_filebuf<CharT>
{
typedef std::basic_filebuf<CharT> base;
typedef typename base::char_type char_type;
typedef typename base::int_type int_type;
typedef typename base::traits_type traits_type;
char_type* eback() const {return base::eback();}
char_type* gptr() const {return base::gptr();}
char_type* egptr() const {return base::egptr();}
void gbump(int n) {base::gbump(n);}
virtual int_type pbackfail(int_type c = traits_type::eof()) {return base::pbackfail(c);}
};
int main(int, char**)
{
{
test_buf<char> f;
assert(f.open("underflow.dat", std::ios_base::in) != 0);
assert(f.is_open());
assert(f.sbumpc() == '1');
assert(f.sgetc() == '2');
typename test_buf<char>::int_type pbackResult = f.pbackfail('a');
LIBCPP_ASSERT(pbackResult == -1);
if (pbackResult != -1) {
assert(f.sbumpc() == 'a');
assert(f.sgetc() == '2');
}
}
{
test_buf<char> f;
assert(f.open("underflow.dat", std::ios_base::in | std::ios_base::out) != 0);
assert(f.is_open());
assert(f.sbumpc() == '1');
assert(f.sgetc() == '2');
typename test_buf<char>::int_type pbackResult = f.pbackfail('a');
LIBCPP_ASSERT(pbackResult == 'a');
if (pbackResult != -1) {
assert(f.sbumpc() == 'a');
assert(f.sgetc() == '2');
}
}
return 0;
}
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