The understanding of synchronous and asynchronous in C language

Now I'm in main.c this file, call 360 browser.

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Analysis process: In the My.exe continue to open another program, so it is related to: My.exe continue to execute whether to wait for the other program to execute after the execution? If you want to wait, it's synchronous; If you don't wait, it's asynchronous. This is the problem of synchronous and asynchronous.

Now is the situation to wait:

The result is to wait until the browser is completely open to print Nihao.

If you look at it this way, it will be clearer:

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The result is:

One to open, and the last to print Nihao

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If you want to asynchronously:

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The result is:

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Three browsers open almost simultaneously, and "Nihao" is printed first.

Because their order of execution is tied, who is lighter and who is fast. This is asynchronous.

At the same time you can see: The default is synchronous.

Summarize:

Synchronization: Is serial execution (in order, a wait), because it is the function of the call principle, the stack mechanism of advanced after the decision, slow, but save resources.

Asynchronous: Is parallel execution (no order, at the same time do), it uses the way to open multi-threaded to achieve at the same time, faster, but will increase the cost of resources;

The two should be used according to the application situation.

In fact, there are many applications of synchronous and asynchronous, such as: The digital circuit has synchronous circuit and asynchronous circuit. The Ajax used in the front and back of the Internet domain also has synchronous and asynchronous points. So synchronous and asynchronous is an important part of learning C language in depth.

This article is from the "C Language good cool" blog, please be sure to keep this source http://ningcaichen66.blog.51cto.com/2902291/1963982

The understanding of synchronous and asynchronous in C language