Undefined Variables in ESP-IDF Examples

[hassankamran012]

Hello, I was reading the example code and some of the variable are not defined that VS Code picks up as errors but is built by idf.py build command without error. Kindly explain why this is. I was specifically looking at the UART echo example.

portTICK_RATE_MS
GPIO_NUM_4
GPIO_NUM_5



Thanks in Advanced.