Defined in header <iostream> extern std::ostream clog; extern
std::wostream wclog; The global objects std::clog and std::wclog
control output to a stream buffer of implementation-defined type
(derived from std::streambuf), associated with the standard C
output stream stderr, but, unlike std::cerr/std::wcerr, these
streams are not automatically flushed and not automatically
tie()'d with cout. These objects are guaranteed to be
constructed before the first constructor of a static object is
called and they are guaranteed to outlive the last destructor of
a static object, so that it is always possible to write to
std::clog in user code. Unless sync_with_stdio(false) has been
issued, it is safe to concurrently access these objects from
multiple threads for both formatted and unformatted output.
static constructor main function static destructor  See also |
initializes standard stream objects | (public member class of |
writes to the standard C error stream stderr, unbuffered| |
writes to the standard C output stre