Really weird function declaration??

[cpjust]

Hi,
While porting some really old C code, I found a lot of function prototypes that look like this:

#ifdef _NW_STDCPROTO_
int
nl_init(
	NL_INFO *info
)
#else
int
nl_init(info)
	NL_INFO *info;
#endif
{
...
}

The strange one is in the #else clause. Why does the init parameter only have the variable name in the parenthesis, and then AFTER it declares it along with the variable type?
Is this the way C worked back in the stone age?
How should you write a function prototype in that case?

[matsp]

Yes, that's the pre-ANSI model of declaration. Most compilers use the former nowadays.

--
Mats

[anon]

I think the else one is a K&R style function declaration. I suppose you don't need the ifdef at all and just use the first.

[Salem]

> Is this the way C worked back in the stone age?
Yes, this is colloquially called K&R C

> How should you write a function prototype in that case?
K&R C didn't have prototypes, only function declarations.
It would typically be written as
extern int nl_init();

Keeping definition and use in agreement without prototypes was one of the reasons for the historic lint program. Prototypes largely fixed the problem (though variadic parameters are still subject to the old rules), and commercial lint programs now find lots of other things to complain about.

[cpjust]

Thanks.
I guess I'll just put the standard prototypes in the header file and save myself a lot of headaches.

[cpjust]

Oh, another question about the K&R style functions:
Some of the functions are defined like this:

int
do_call(cid, inbuffer, inlength, outbuffer, outlength, count, ret)
NL_CONNECTION_ID cid;
unsigned short *inbuffer, *outbuffer;
unsigned inlength, outlength;
unsigned count;
int ret;
{ ... }

If you notice, the order of the names in the parameter list is different than the order that they are declared before the function body.
In this case, which order will the compiler use? i.e. Would you call the function the way it looks, or do you pass the parameters in the order they're declared: do_call( cid, inbuffer, outbuffer, inlength, outlength, count);

[matsp]

The parameters are used in the order they are listed in the parenthesis in the function header, not in the order you define what type which parameter is.

This is so that you can do (stupid) things like this:

int blah(a, b, c, d, e, f)
char *a, *c, *e;
int b;
float d, f;
{
}

That saves wear and tear on the fingers. (Remember, text-editors in the day when C was invented didn't have click-drag-right-click-select-copy-move-select-right-click-paste stuff. And nor did they have much of the auto-completion that we have nowadays.

[There's a joke in programmer circles about "cobol fingers", since Cobol is a very "wordy" language, you'd wear them out, so "cobol fingers" is when your fingers are just short stumps rather than "full length"].

--
Mats