Weird (?) explicit declaration of functions

[Nils Emil P. Larsen]

Hello

I have read about a C shared library which I want to use in my C
program. (It's a library to encode/decode packets from/to a serial bus
running with the SNAP-protocol).

Unfortunatly there is no source code available, just a C file with
function declarations like:

long SendData(TXData )Type_TXData *TXData;
Void GetStatistics(S tat)Type_Statis tics *Stat;

My problem is, I don't understand what it means. Is it equivalent to
long SendData(Type_T XData *TXData);
- which makes a lot more sense to me?

Is there a good reason to use this strange syntax?

Nils Emil
--
My reply-address is valid. www.bios-flash.dk
Min svar-adresse er gyldig. Redning af døde BIOS'er

[Joona I Palaste]

Nils Emil P. Larsen <ne********@pos t.cybercity.dk> scribbled the following:

Hello I have read about a C shared library which I want to use in my C
program. (It's a library to encode/decode packets from/to a serial bus
running with the SNAP-protocol). Unfortunatly there is no source code available, just a C file with
function declarations like: long SendData(TXData )Type_TXData *TXData;
Void GetStatistics(S tat)Type_Statis tics *Stat; My problem is, I don't understand what it means. Is it equivalent to
long SendData(Type_T XData *TXData);
- which makes a lot more sense to me?
It appears to be a K&R1-style declaration, which predates ISO C, and is
now considered obsolete.
Is there a good reason to use this strange syntax?

No, if not for legacy compability.

--
/-- Joona Palaste (pa*****@cc.hel sinki.fi) ------------- Finland --------\
\-- http://www.helsinki.fi/~palaste --------------------- rules! --------/
"Life without ostriches is like coffee with milk."
- Mika P. Nieminen

[Chris Torek]

>Nils Emil P. Larsen <ne********@pos t.cybercity.dk> scribbled the following:

... Unfortunatly there is no source code available, just a C file with
function declarations like:
long SendData(TXData )Type_TXData *TXData;
Void GetStatistics(S tat)Type_Statis tics *Stat;
In article <cb**********@o ravannahka.hels inki.fi>
Joona I Palaste <pa*****@cc.hel sinki.fi> writes:

It appears to be a K&R1-style declaration, which predates ISO C, and is
now considered obsolete.
While:

Tfunc funcname(arg1, arg2)
Targ1 arg1;
Targ2 arg2;

is indeed K&R-1 ("pre-ANSI" or "Classic C") syntax, it is not valid
as a *declaration*, only as a *definition*, and it must be followed
by the open brace of the function, e.g.:

int main(argc, argv)
int argc;
char **argv;
{
/* local variables here */
...
return 0;
}

The parameters "argc" and "argv" become local (block-scope) variables
inside the function in the usual way, just as with prototype-syntax
parameters. (The fact that the scope of argc and argv is the same as
that of any block-scope variable declared right after the "{" is the
reason I eventualy adopted the indentation shown above, for K&R-1 C.)

At least one K&R-style compiler would, if given something like the
above as a declaration, do something very bad:

void f1(arg) int arg; /* ERROR -- no function body */
char *f2(arg) char *arg; /* ERROR -- no function body */
int main(argc, argv) int argc; char **argv; { ... }

Here the variables "argc" and "argv" would exist as one expected,
but have the wrong internal addresses, and the stack would get
wrecked.
Is there a good reason to use this strange syntax?

No, if not for legacy compability.

Indeed.
--
In-Real-Life: Chris Torek, Wind River Systems
Salt Lake City, UT, USA (40°39.22'N, 111°50.29'W) [phone]
email: forget about it http://web.torek.net/torek/index.html
Reading email is like searching for food in the garbage, thanks to spammers.