Arduino IDE does not recognize "__time_critical_func" attribute

[XFer012]

RESOLVED:
__time_critical_func is not an attribute. The correct declaration is:

void __time_critical_func (myISRroutine)()

and not

void __time_critical_func myISRroutine()

Sorry for the useless post.
I leave it here for reference.

Hello,
Arduino IDE 2.3.2 on Windows 11, latest Arduino-Pico core v4.0.1

I'm trying to put a ISR in RAM, so I defined it as

#include <pico/stdlib.h>

void __time_critical_func myISRroutine()
{
...
}

Unfortunately the compiler does not recognize the attribute:

error: expected initializer before 'myISRroutine'
  350 | void __time_critical_func myISRroutine()

Maybe I included the wrong header? Is it not pico/stdlib.h?

Thanks!

[earlephilhower]

Use __not_in_flash_func(x) instead.