static_assert(sizeof(qsbr_epoch_t) == 8, "expected 64-bit counter")

[clausecker]

This assertion checks if qsbr_epoch_t is a 64 bit type:

static_assert(sizeof(qsbr_epoch_t) == 8, "expected 64-bit counter")

However, the code defines qsbr_epoch_t to be of type

typedef unsigned long qsbr_epoch_t;

which may be a 32 bit type. Please change the code such that qsbr_epoch_t is instead a 64 bit type:

typedef unsigned long long qsbr_epoch_t;