An 8266 crash

8266 This can't be debugged in real time , The problem can only be confirmed by printing an error message . When connecting serial port , If it crashes, it will print errors. You can refer to this blog ESP8266/ESP32 Program crash (crash) Positioning method 1 when ： Register and call stack (backtrace)_ Lexin technology Espressif The blog of -CSDN Blog _esp32 register I also have a crash here , Errors may be inconsistent , It feels like the stack is broken , Checking the code over and over again seems to have no errors . Commented a lot of code , Still collapse . Finally, it was found that it was because the return type was defined , But it didn't actually return .... This is a very low level mistake , But it's also common , Because a lot of API The design may assume that it returns a value , But in the end, you may find that you don't need it to return anything , In this case, the compiler usually gives a warning when compiling . however 8266 There is no output in the compilation environment of , Of course, it may be a compiler compilation setting problem . Keep a record so that no one else will step on the pit .