Function-doubt

Hello, this wierd question just came to my mind.

Why isnt it possible to call a function which takes no arguments with a function call as argument which does not return any value (which imho is equivalent to calling a function which takes no arguments with no arguments).

f.e.

Code:

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void foo(void) {...}
void bar(void) {...}

foo(bar())

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Dont get me wrong, i know void is not a value and that it can not be treated like one.

With my logic it would make sense and it should be possible to do that. I mean, why not? Any argument why that should not be possible?

Let me hear your opinions about this.

Specifying void in a functions argument list does not make it argument for that function, it only says that the function takes no arguments. Thats all.

florian thankz for your reply,
but can you please elaborate,
I mean bar() return nothing then doesn,t it mean that foor function expect nothing on invoking
through function call foo(bar())

You'll have compile-time error for foo(bar()) since foo() does not take any parameter and bar() returns nothing. lol!

but compiler can check through function prototype that bar() will return nothing means
foo(bar()) shld be equivalent to foo()..????????

Have you tried to compile it?
gcc foobar.c
foobar.c::error: too many arguments to function ‘foo’

i think i am bit confuse about void and null
well i have checked thats why i am asking here that why compiler can,t check or how it interpret
that if boo function return nothing , then why it can,t use for a function who accept no argument
BTW thankz

Quote:

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Originally Posted by fluteofliar

i think i am bit confuse about void and null

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NULL == 0. Think of it this way:

#define NULL 0

After running this code:

int var;
var = NULL;

"var" will contain "0".

void == no variable exists in the first place.

It makes more sense to declare a function as func() rather than func(void).

Quote:

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Originally Posted by fluteofliar

that if boo function return nothing , then why it can,t use for a function who accept no argument

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1) Because it doesn't make any sense to allow it.

2) The compiler looks for things between the ()s before checking their type.

Code:

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int var;
var = NULL;

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It's very poor practice. Use NULL only for pointer.
NULL may be defined as (void*)0.

Quote:

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Originally Posted by Bayint Naung

Code:

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int var;
var = NULL;

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It's very poor practice. Use NULL only for pointer.
NULL may be defined as (void*)0.

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I know, and I would never use NULL for anything but pointers.

I was just trying to explain it to the original poster that the concepts of "NULL" and "void" are completely unrelated.