Getting the file-mode from the FILE struct?

I have a piece of C code, a function to be specific, which operates on a FILE*.

Depending on which mode the FILE* was opened with there are certain things I can and cannot do.

Is there any way I can obtain the mode the FILE* was opened with?

That FILE* is all the info I can rely on, because it is created somewhere else in the program and the actual file-name is long lost before it reaches my function, and this I cannot influence.

I would prefer a portable solution.