Summary of some classic embedded C interview questions

#error What is the role of ？

#error   The instruction causes the preprocessor to issue an error message , And it interrupts the compilation process . So let's start with Linux Extract a small piece of code from the code and modify it to get the sample code ：

This sample code is simple , When RX_BUF_IDX The value of the macro is not 0~3 when , In the preprocessing phase, it goes through  #error   The command outputs an error message ：

"Invalid configuration for 8139_RXBUF_IDX"

Let's compile and take a look at the results ：

Recommended articles ： Get to know #pragma、#error Instructions