Arduino for STM32

Hello,
How can I make a custom function handling the specific vector address ISR routine given by the data sheet (in pure c) please ?
in fact I have the hexadecimal vector address (from data sheet) and I just want to make a function pointing on that physical addresse
that should be a simple basic routine but it's not clear in my mind yet
because function pointer is a pointer on a function but what I want is a function at a
specific runtime address ?
Thanks.

because function pointer is a pointer on a function but what I want is a function at a
specific runtime address ?

putting a function at a specific address is compiler specific. read the manual for your compiler.

more importantly, why do you want to put a function at a specific address? presummably you want to execute it - which is the same thing practically as calling that function from the isr, via a function pointer or otherwise.