bind() 和 lambda 表达式都可以实现类似的功能，在使用的时候有时候不知道选择哪一个。这里来做一个简单的总结。主要参考了一下的文章：
http://stackoverflow.com/questions/1930903/bind-vs-lambda
http://www.gockelhut.com/c++/articles/lambda_vs_bind
1. bind() 在多层嵌套的时候会使代码非常难看懂（参见文章一）
2. lambda 不支持“多态性”（其实就是泛型），需要在定义的时候指定参数类型
3. lambda 运行速度会比bind() 函数快很多
4. lambda 可以通过 std::function 实现“多态”特性
下面是一个例子，表明lambda 的运行时间比bind 的情况要快很多：
#include <cstdint> #include <chrono> #include <iostream> #include <string> #include <functional> #include <thread>class timer { public:typedef std::chrono::high_resolution_clock clock;typedef clock::time_point time_point;typedef clock::duration duration;public:timer(){reset();}void reset(){_starttime = clock::now();}duration elapsed() const{return clock::now() - _starttime;} protected:time_point _starttime; };template <typename T> void volatile_write(const T& x) {volatile T* p = new T;*p = x;delete p; }template <typename Function> void run_test(const std::string& name, Function func) {std::cout << name;timer t; //初始化的时候已经开始计时volatile_write(func());timer::duration duration = t.elapsed();std::cout << '\t' << duration.count() << std::endl; }template <typename Function> void do_test_loop(Function func, const uint64_t upper_limit = 100000) {for (uint64_t i = 0; i < upper_limit; ++i)func(i); }uint64_t test_accumulate_lambda() {uint64_t x = 0;auto accumulator = [&x] (uint64_t i) { x += i; };do_test_loop(accumulator);return x; }void test_accumulate_bind_function(uint64_t& x, uint64_t i) {x += i; }uint64_t test_accumulate_bind() {namespace arg = std::placeholders;uint64_t x = 0;std::function<void (uint64_t)> accumulator = std::bind(&test_accumulate_bind_function, std::ref(x), arg::_1);do_test_loop(accumulator);return x; } uint64_t test_accumulate_bind_auto() {namespace arg = std::placeholders;uint64_t x = 0;auto accumulator = std::bind(&test_accumulate_bind_function, std::ref(x), arg::_1);do_test_loop(accumulator);return x; }uint64_t test_accumulate_bound_lambda() {uint64_t x = 0;std::function<void (uint64_t)> accumulator = [&x] (uint64_t i) { x += i; };do_test_loop(accumulator);return x; }int main() {run_test("Accumulate (lambda) ", &test_accumulate_lambda);run_test("Accumulate (bind) ", &test_accumulate_bind);run_test("Accumulate (bound lambda) ", &test_accumulate_bound_lambda);run_test("Accumulate (bind_auto) ", &test_accumulate_bind_auto);return 0; }
运行结果：
C:\Windows\system32\cmd.exe /c lambda_vs_bind.exe
Accumulate (lambda) 20001
Accumulate (bind) 110007
Accumulate (bound lambda) 50003
Accumulate (bind_auto) 90005
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从运行结果可以看出，使用lambda比bind快一个数量级，使用auto 修饰函数对象比用std::function<>速度也略有提升。