What does it mean when a C function pointer has a void parameter?

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C void arguments

I am looking at some OpenGL graphics code and it has the following:

glutIdleFunc(void(*func)(void));

When does it mean to have a function pointer with a void argument in C? Does this mean the function can take in any arguments or is not allow to take in any arguments, or something else?

It means that the function takes no arguments. See [this answer](http://stackoverflow.com/a/693794/275567). — pb2q, Sep 30 '12 at 20:14
It's a function pointer to a function that takes no arguments and returns nothing. Note that the function pointer may be casted and this may be only a place holder for arbitrary function pointers to be passed to the function `glutIdleFunc` — stefan, Sep 30 '12 at 20:21

score 3 · Accepted Answer · edited Sep 30 '12 at 20:17

3

It means you have to pass a pointer to a function that has no parameters and returns nothing.

edited Sep 30 '12 at 20:17

Eric Postpischil

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answered Sep 30 '12 at 20:15

ouah

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score 0 · Answer 2 · answered Sep 30 '12 at 20:23

void func(void) is a function that takes no parameters and does not return anything.

This is not to be confused with: void func() which in C (not C++) is a function that has no parameter checking, and does not return anything.

This is not to be confused with: func(void) which is a function which takes no parameters and returns an int, by default.

What does it mean when a C function pointer has a void parameter?

2 Answers2