Second Try - Suppress stdout from shared libraries

[Frederick Gotham]

I'm writing a program that links with a handful of shared libraries.
Some of the shared libraries write the occassional infrequent message to
stdout.

I want to suppress the messages outputted from these shared libraries,
namely from statements such as the following:

cout << "whatever" << some_number << endl;
printf("whatever%i\n", some_number);

However I want my own program to still be able to use "cout" to print to
stdout. (I don't have any use for "printf" or any related C-style IO
functions in my pgrogram).

So the first thing I've done is allocated static duration memory for an
'ostream' object. My object is called "g_exclusive_cout":

std::aligned_union<0, std::ostream>::type g_exclusive_cout;

My program is for Linux and so I've started by coding a Linux-specific
solution, however I'm curious as to whether there's a C++11 ANSI/ISO
portable solution.

Next I call the following function when the program starts:

void Suppress_Cout_From_Shared_Libraries(void)
{
fflush(stdout);

static __gnu_cxx::stdio_filebuf<char>
filebuf(dup(fileno(stdout)), std::ios::out);

freopen("/dev/null", "w", stdout);

::new(&g_exclusive_cout) std::ostream(&filebuf);
}


And then lastly I have a macro for exclusive cout, "excout":

#define excout ( \
*static_cast<std::ostream*>( \
static_cast<void*>(&g_exclusive_cout) \
) \
)

And so then in my own program, I always use "excout" instead of "cout",
for example:

int main(void)
{
Suppress_Cout_From_Shared_Libraries();

excout << "Hello World!" << endl;
}

This solution works for me. Of course I've used POSIX-specific functions
and GNU compiler extensions to pull it off. I wonder if there's an
ANSI/ISO C++11 way of doing it? By the way, since multithreading was
introduced into C++11, there is a gaurantee that calls to "cout <<
whatever" are thread-safe. I wonder if my own code with "excout" is
thread-safe, or whether I'll have to wrap methods called on "excout"
within a mutex?