[Bug libstdc++/11584] ios::iword() fails to zero-initialize storage on failure

[bkoz at gcc dot gnu dot org]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11584



------- Additional Comments From bkoz at gcc dot gnu dot org  2003-09-17 23:45 -------

On closer examination, I don't think this is a bug. 

For one thing:

    int i = std::ios::xalloc();
    std::cout.iword (i) = 0xdeadbeef;
    long l = std::cout.iword (i);
    l == 0xdeadbeef;

is valid, based on the fact that the index is the same (regardless of the
replacement operator new). 

If, instead:

void test01()
{
  bool test = true;
  new_fails = 1;

  const int i = std::ios::xalloc();
  std::cout.iword(i) = 0xdeadbeef;
  long l1 = std::cout.iword(i);
  VERIFY( l1 == 0xdeadbeef);
 
  long l2 = std::cout.iword(i * 3);
  VERIFY( l2 == 0 );

  // The reference returned may become invalid after another call to
  // the object's iword member with a different index.  NB: Note the
  // 'may': it's not required, and in this case should not be
  // required, as the i size array is still allocated.
  long l3 = std::cout.iword(i);
  VERIFY( l3 == 0 || l3 == 0xdeadbeef);
}

-benjamin