https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118665
Bug ID: 118665
Summary: std::uniform_int_distribution infinite loop with
generator returning 0
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: cgnitash at gmail dot com
Target Milestone: ---
Passing a custom generator that always returns 0 to
std::uniform_int_distrubtion<int> causes it to hang (presumably due to an
infinite loop)
#include <random>
class Gen {
public:
using result_type = std::mt19937::result_type;
Gen() : rng(0) {}
static constexpr result_type min() { return std::mt19937::min(); }
static constexpr result_type max() { return std::mt19937::max(); }
// always return 0
result_type operator()() { return 0; }
private:
std::mt19937 rng;
};
int main() {
Gen g;
std::uniform_int_distribution<int> dist(0, 42);
return dist(g); // hangs
}
This only happens when operator() returns exactly 0.
libc++ doesn't have this issue.
Demo: https://godbolt.org/z/E8M5dhE59
