memcheck/tests/realloc_size_zero_mismatch.cpp

   1 #include <iostream>
   2 #include <cstdlib>
   3 #include <cstdio>
   4 #include <cerrno>
   5
   6 using std::realloc;
   7 using std::cout;
   8 using std::perror;
   9
  10 int main(void)
  11 {
  12    char* p = new char[1024];
  13    p[0] = '\0';
  14    errno = 0;
  15    // mismatch
  16    p = static_cast<char *>(realloc(p, 0));
  17    if (p) {
  18       cout << "p not nullptr after realloc 0\n";
  19    } else {
  20       cout << "p is nullptr after realloc 0\n";
  21    }
  22    if (errno) {
  23       perror("realloc(something, 0):");
  24    }
  25    // mismatch again
  26    delete [] p;
  27
  28    errno = 0;
  29    volatile void *ptr = NULL;
  30    volatile size_t size = 0U;
  31    char *p2 = static_cast<char *>(realloc(const_cast<void*>(ptr), size));
  32    if (p2) {
  33       cout << "p2 not nullptr after realloc 0\n";
  34    } else {
  35       cout << "p2 is nullptr after realloc 0\n";
  36    }
  37    if (errno) {
  38       perror("realloc(NULL, 0):");
  39    }
  40    // mismatch
  41    delete [] p2;
  42 }