test code for SCNu8.

testSCNu8.cpp

/**
 * test code for SCNu8
 * Copyright (c) 2016 Koichi OKADA. All rights reserved.
 * This code is distributed under the MIT license.
 *
 * References:
 * - MSDN / Visual Studio 2013 / [scanf Width Specification](https://msdn.microsoft.com/en-us/library/xdb9w69d(v=vs.120).aspx)
 * - MSDN / Visual Studio 2015 / [scanf Width Specification](https://msdn.microsoft.com/en-us/library/xdb9w69d(v=vs.140).aspx)
 * - die.net / [vscanf(3)](http://linux.die.net/man/3/vscanf)
 * - JM / [scanf(3)](https://linuxjm.osdn.jp/html/LDP_man-pages/man3/scanf.3.html)
 */
#include <cstdio>
#include <cstdlib>
#include <cstdint>
#include <cinttypes>
#include <cstring>
#include <cassert>

#ifndef SCNu8 // for Cygwin64 x86_64-w64-mingw32-g++ 5.4.0
#define SCNu8 "hhu"
#endif

#ifndef PRIzu
#if __STDC__ || _MSC_VER >= 1900
#define PRIzu "zu"
#elif _MSC_VER
#ifdef _WIN64
#define PRIzu "llu"
#else//_WIN32
#define PRIzu "u"
#endif
#else
#error "PRIzu could not be determined."
#endif
#endif

#define TOSTR(X) # X
#define DUMP(V) {printf("%s: ", #V); dump(V);}

template<class T>
inline void dump(T &v)
{
  uint8_t *p = reinterpret_cast<uint8_t *>((void *)&v);
  printf("%p(%" PRIzu "):", p, sizeof(T));
  
  for (int i = -4; i < 8; i++) {
    printf(" %02x", p[i]);
  }
  printf("\n");
}

bool testSNCu8()
{
  char x[12] = {0};
  char y[12] = {0, 0, 0, 0,-1, 0, 0, 0, 0, 0, 0, 0};
  
  printf("SCNu8 = \"%s\"\n", SCNu8);
  DUMP(x[4]);
  printf("%s\n", TOSTR(sscanf("-1", "%" SCNu8 "", &x[4]);));
  ;                    sscanf("-1", "%" SCNu8 "", &x[4]);
  DUMP(x[4]);
  return memcmp(x, y, sizeof(x)) == 0;
}

int main(int argc, char *argv[])
{
  assert(testSNCu8());
  
  return EXIT_SUCCESS;
}