Thread separated random int generation in C++ - c++

Question

I need to genetate three .txt files filled with random int, calling the generate function in sepatared threads.
The problem is that as a result I have the same values in every .txt files.
A function that gererates and writes values:
void generateMoves(int limit, std::string outputPath) {
//open fstream
std::ofstream fout;
fout.open(outputPath);
if (!fout.is_open()) {
std::cout << "Error reading " << outputPath << " file. Exiting..." << std::endl;
exit(1);
}
static thread_local std::mt19937 generator;
std::uniform_int_distribution<int> distribution(1, 3);
//generating & writing moves
for (int i = 0; i < limit; i++) {
int value;
value = distribution(generator);
fout << value << std::endl;
}
fout.close();
}
I call threads like this from main():
int limit = 1000;
std::thread player1(generateMoves, limit, "player1.txt");
std::thread player2(generateMoves, limit, "player2.txt");
std::thread player3(generateMoves, limit, "player3.txt");
player1.join();
player2.join();
player3.join();
So, how do I separate int generation correctly?
Edit: Following the comment below, I putted diffent seed into each thread and everything works fine now. The random generation looks like this now:
// put different *s* into each thread
srand(s);
//generating & writing
for (int i = 0; i < limit; i++) {
int value;
value = rand() % 3 + 1;
fout << value << std::endl;
}

Answer 1

As the comments state, all your generators have been created from the same default seed. It suffices to give each generator a different seed:
std::random_device rd1;
static thread_local std::mt19937 generator(rd1());
This uses the (very slow) std::random_device, but only to generate a unique seed for the mt generator.