libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetc.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // <streambuf>
  10
  11 // template <class charT, class traits = char_traits<charT> >
  12 // class basic_streambuf;
  13
  14 // int_type sgetc();
  15
  16 #include <streambuf>
  17 #include <cassert>
  18
  19 #include "test_macros.h"
  20
  21 int underflow_called = 0;
  22
  23 struct test
  24     : public std::basic_streambuf<char>
  25 {
  26     typedef std::basic_streambuf<char> base;
  27
  28     test() {}
  29
  30     void setg(char* gbeg, char* gnext, char* gend)
  31     {
  32         base::setg(gbeg, gnext, gend);
  33     }
  34
  35 protected:
  36     int_type underflow()
  37     {
  38         ++underflow_called;
  39         return 'a';
  40     }
  41 };
  42
  43 int main(int, char**)
  44 {
  45     {
  46         test t;
  47         assert(underflow_called == 0);
  48         assert(t.sgetc() == 'a');
  49         assert(underflow_called == 1);
  50         char in[] = "ABC";
  51         t.setg(in, in, in+sizeof(in));
  52         assert(t.sgetc() == 'A');
  53         assert(underflow_called == 1);
  54         assert(t.sgetc() == 'A');
  55         assert(underflow_called == 1);
  56     }
  57
  58   return 0;
  59 }