Declaring and initializing a variable in a Conditional or Control statement in C++

Question

In Stroustrup\'s The C++ Programming Language: Special Edition (3rd Ed), Stroustrup writes that the declaration and initialization of variables in the conditionals

Answer 1

Adding to what RedGlyph and Ferruccio said. May be we can do the following to still declare within a conditional statement to limit its use:

if(int x = read(socket)) //x != 0
{
  if(x < 0) //handle error
  {}
  else //do work
  {}
}
else //x == 0  
{
  return true;
}