Restrict use of functions in a kata

[bitcanon]

When writing a kata there are often two options available for solving it:

• Write your own code using the language operators and your own functions
• Use external libraries that does it all for you

I want the user to gain a deeper understanding of a subject when solving the kata. In order to do that the user should use, for example, bitwise operators. The user could also use a built-in function that solves the entire kata in one line, but still have no idea how it works under the hood.

My question is (specifically for the C language), is there a way to prohibit the use of:

• A specific function (for example pow())
• An entire include file (for example math.h)

Thanks in advance.

[Blind4Basics]

https://docs.codewars.com/authoring/guidelines/submission-tests/#tests-with-additional-restrictions
especially, read the last point, plz

Note: I don't do C myself, so I cannot tell anything more...

[interrupt-routine]

You can disable a C function by writing a dummy function with the same name in setup.c (preloaded) or fixture.c (tests)
Be careful since most math.h functions exist in 3 flavors for float ('f' suffix), double (no suffix) and long double ('l' suffix) e.g. powf(), pow(), powl()
Disabling a header is not very useful, since undeclared functions just emit a warning, and user can just copy-paste the declarations they need anyway.

[bitcanon]

Perfect, this is exactly the answer I was looking for. Thanks!