#extern The main function of "C" is to correctly implement C code to call other C language codes.
After adding extern "C", the compiler will be instructed to compile this part of the code in C language (not C). Since C supports function overloading, when the compiler compiles a function, it will also add the parameter type of the function to the compiled code, not just the function name; and the C language does not support function overloading, so compiling C The function of the language code does not include the parameter type of the function, generally only the function name is included.
This function is very useful, because before C appeared, many codes were written in C language, and very low-level libraries were also written in C language. In order to better support the original C code and the already written A good C language library needs to support C in C as much as possible, and extern "C" is one of the strategies.
This function is mainly used in the following situations:
1. C code calls C language code;
2. In the C header file Use;
3. When multiple people collaborate on development, some people may be better at C language, while others are good at C. It will also be useful in this case.
Recommended tutorial: C language tutorial
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