std::generate_canonical can generate 1.0, which does not conform to the c++11 standard. On my box the following program yields "Bug!":

#include <iostream>
#include <limits>
#include <random>

int main()
{
    std::mt19937 rng;

    std::seed_seq sequence{0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    rng.seed(sequence);
    rng.discard(12 * 629143 + 6);

    float random = std::generate_canonical<float,
                   std::numeric_limits<float>::digits>(rng);

    if (random == 1.0f)
    {
        std::cout << "Bug!\n";
    }

    return 0;
}

See also http://stackoverflow.com/questions/25668600/is-1-0-a-valid-random-number for a longer discussion and analysis of the problem.

I first noticed this on my system GCC,

gcc (Gentoo 4.7.3-r1 p1.4, pie-0.5.5) 4.7.3
Copyright (C) 2012 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

but I can reproduce the same behavior with a recent GCC from git:

gcc (GCC) 5.0.0 20140830 (experimental)
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

I used `c++ =std=c++11` to compile the program above.