What is the purpose of UNUSED_VARIABLE() when the effect is the same without it?

[helpme]

I am using SDK_11 s130. I am looking at app_error_fault_handler() in app_error_weak.c

Inside app_error_fault_handler(), there is this line of code;

UNUSED_VARIABLE(bsp_indication_set(BSP_INDICATE_FATAL_ERROR));

This line of code will cause all 4 LEDs in nRF-51 board to light up. The strange thing is that when I remove UNUSED_VARIABLE, the same outcome can be achieved without side effect. I am puzzled what is the purpose of UNUSED_VARIABLE() as it is used in many places.

[Thomas R.]

This is just a macro for a cast to void.

Normally this is used to make it clear that the return value is ignored on purpose and has not just been forgotten. This will suppress warnings from the compiler, if enabled (for GCC its the -Wunsused-result option), butit is also a good style of coding, especially if the code is used by other people, too.

[helpme]

Thanks. I find it unusual to call it UNUSED_VARIABLE. After all, the command within brackets will be called.