IO model and those things that eat

I wrote it blindly. Everyone has a good time after reading the picture. If it is wrong, please correct me.

blocking IO

Wanxiang Lou has opened. Today is the first day to receive people. Zhang San is the first guest. He glanced at the menu and said to recvfrom : "Bring me a bowl of saozi noodles, put more saozi .", recvfrom politely: "Okay, wait a minute, I'll make it for you right away." After 20 minutes of doing this, Li Si, Wang Wu, and Ma Liu who were in line behind them were unwilling. Li Si said impatiently: "Boss, can you hurry up, you will faint when you are doing this!"

non-blocking IO

recvfrom said politely to Li Si: "I'm sorry, I have a little less preparation, I will compensate you EWOULDBLOCK Let's change it first.", Li Si thought There was no point in continuing to wait, so he turned and walked away.

IO reuse model

Wang Wu and Ma Liu felt that they had been queuing for so long. After thinking about it, it was not the way to go. They didn't know if the next house would have to wait in line like this. It happened that a large number of people poured in at this time. Wang Wu thought for a while and said: "Boss, let's do it, I happen to have two sets of number cards fd , you can use them first, after everyone orders, you will send one, and you will be ready. After that, you put it on the designated number plate, and then let your 8-year-old baby select/poll|epoll look at it. If it is done, let your baby say it according to the number plate, and then we will pick it up by ourselves. I'm done." The boss showed grateful eyes and thanked Wang Wu repeatedly. So everyone ordered food in an orderly manner. The boss's big bone rice and braised pork rice were enough. Several people ordered them and got them and sat down to eat. Several people ordered some shredded pork with Beijing sauce, shaozi noodles, etc. They were not ready yet, so they sat beside them and quietly brushed their phones and waited.

Signal-driven IO model

Wang Wu and Ma Liu sat for a while, Ma Liu saw the boss and children looking at the number plates and running around, sweating profusely, so he poked Wang Wu next to him: "Your number plate It's all for the boss, there's no need to watch it, you have the boss's corresponding number ready to call SIGIO isn't the designated number enough?"

Wang Wuyi patted his thigh: "Hey, that's the truth, let me tell you."

Asynchronous IO model

Just at this time, the boss's wife came. The boss felt that many people had been waiting for a long time, so he said to his wife: "After my dishes are ready, you will follow this number plate to find the corresponding number of guests, and put Bring it to them, so that guests don't have to run around all the time. They just have to order and sit down."