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Editorial Team
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Asked: 2026-05-16T22:52:06+00:00

I’ve declared many functions in one driver, and am passing the pointers to the

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I’ve declared many functions in one driver, and am passing the pointers to the functions to another driver in a list with the node format:

struct node
{
 char def_prototype[256]; //example:(int (*)(wchar, int, int))
 void *def_function;
};

Is there a way to typecast def_function to the prototype given in def_prototype?

Currently I’m using simple switch and strcmp, but I wanted to generalize it if possible.

PS: I know that casting between void pointer and function pointer is unsafe (as mentioned in various places in SO), but desperate times call for desperate measures and I have taken lot of care.

EDIT:
Sorry for the lack in clarity. I want to actually call the function (not just cast it), making a function pointer at runtime based on the char[] provided.

EDIT AGAIN:
Since I’m working at the kernel level (windows driver), I don’t have access to much resources, so, I’m sticking to my current implementation (with some changes to kill back-doors). Thanks to all for your help.

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1 Answer

  1. Editorial Team

    A good implementation of similar ideas is libffi. This implements the gory details of declaring and calling functions with arbitrary calling conventions and signatures. It is (surprisingly) platform portable, and known to work on Linux and Windows out of the box.

    An example of its use is the Lua extension library alien. That demonstrates calling arbitrary functions declared at runtime and adapting from native Lua types to the types required for the calling conventions. The specific Lua binding won’t be useful to you, but it serves as a complete working example of how and why one might actually use libffi.

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