libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.members/streambuf.pub.get/sgetn.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 // streamsize sgetn(char_type* s, streamsize n);
  15
  16 #include <streambuf>
  17 #include <cassert>
  18
  19 #include "test_macros.h"
  20
  21 int xsgetn_called = 0;
  22
  23 struct test
  24     : public std::basic_streambuf<char>
  25 {
  26     test() {}
  27
  28 protected:
  29     std::streamsize xsgetn(char_type*, std::streamsize)
  30     {
  31         ++xsgetn_called;
  32         return 10;
  33     }
  34 };
  35
  36 int main(int, char**)
  37 {
  38     test t;
  39     assert(xsgetn_called == 0);
  40     assert(t.sgetn(0, 0) == 10);
  41     assert(xsgetn_called == 1);
  42
  43   return 0;
  44 }