Function key_usable

thread/thread-key.cpp:33–35

A program would have to create and destroy a key 2^63 times to overflow the sequence */

/* A program would have to create and destroy a key 2^63 times to overflow the sequence */
static inline bool key_usable(uint64_t key) {
    return key < key + 2;
}

struct thread_key_data {
    uint64_t seq;