分段错误(malloc struct)

你永远不用于分配空间comp->highest_committed_vs,你检查comp的NULL非关联化之后.试试这样吧

int main() 
{
    consensus_component *comp = malloc(sizeof(consensus_component));
    if (comp == NULL)
        return -1;
    memset(comp, 0, sizeof(consensus_component));
    comp->highest_committed_vs = malloc(sizeof(*comp->highest_committed_vs));
    if (comp->highest_committed_vs == NULL)
    {
        free(comp);
        return -1;
    }

    comp->highest_committed_vs->view_id = 1; 
    comp->highest_committed_vs->req_id = 0;

    db_key_type start = vstol(comp->highest_committed_vs)+1;
    printf("%" PRIu64 "\n", start);

    return 0;
}