#include <flecs.h>
#include <iostream>

struct Position {
    float x, y, z;
};
struct Velocity {
    float vx, vy, vz;
};
int main(int argc, char *argv[]) {
    flecs::world ecs(argc, argv);
    auto person_prefab = ecs.prefab("PersonPrefab")
        .set<Position>({0, 0, 0})
        .set<Velocity>({0, 0, 0});
    for (int i = 0; i < 50000000; i++) {
        ecs.entity()
            .is_a(person_prefab)
            .add<Position>()
            .set<Position>({static_cast<float>(i), 0, 0});
    }
    std::cout << "Created 50,000,000 entities" << std::endl;
    return 0;
}

Created 50,000,000 entities
fatal: allocator.c: 52: assert: size >= 0 INTERNAL_ERROR
1   TestECS                             0x0000000102a45aa8 flecs_log_msg + 1676
2   TestECS                             0x00000001029ac20c ecs_printv_ + 212
3   TestECS                             0x00000001029ac398 ecs_log_ + 100
4   TestECS                             0x00000001029ac118 ecs_assert_log_ + 264
5   TestECS                             0x0000000102a0b184 flecs_allocator_get + 72
6   TestECS                             0x0000000102a17c70 ecs_vec_set_size + 212
7   TestECS                             0x0000000102a18038 ecs_vec_append + 88
8   TestECS                             0x0000000102a78af0 flecs_cmd_new + 40
9   TestECS                             0x0000000102a78c14 flecs_defer_delete + 44
10  TestECS                             0x0000000102a224fc ecs_delete + 324
11  TestECS                             0x0000000102aa0174 flecs_fini_root_tables + 1164
12  TestECS                             0x0000000102a9aa88 flecs_fini_roots + 148
13  TestECS                             0x0000000102a9a6d4 ecs_fini + 1096
14  TestECS                             0x0000000102994f50 _ZN5flecs5world7releaseEv + 140
15  TestECS                             0x0000000102994eac _ZN5flecs5worldD2Ev + 28
16  TestECS                             0x000000010296ab80 _ZN5flecs5worldD1Ev + 28
17  TestECS                             0x000000010296a894 main + 440
18  dyld                                0x0000000190de8274 start + 2840

Process finished with exit code 134 (interrupted by signal 6:SIGABRT)