[U-Boot-Users] about "env_init"

hello,all In the file Env_flash.c ,there is a function as

#ifdef CFG_ENV_ADDR_REDUND int env_init(void) { DECLARE_GLOBAL_DATA_PTR; ... }

What's CFG_ENV_ADDR_REDUND mean?on which condition the function env_init(void) works. and I want to know when env store in flash,where to store,and how to store the env and how can i get it from flash

thanks a lots

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