Prototype function definition

[grk.jkb]

Hi, i am using a tool developed in C and i use "make all" command to run. But the following error occur:

cc -O -DUNIX -DBSD -g -I/home/English/morph-1.5/hash -I/usr/include/X11/Xaw -c -w -o lib/bcopy.o /home/English/morph-1.5/hash/bcopy.c
/home/English/morph-1.5/hash/bcopy.c: In function ‘bcopy’:
/usr/include/bits/string3.h:90: error: old-style parameter declarations in prototyped function definition
make: *** [lib/bcopy.o] Error 1

and the program is given below

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)bcopy.c 5.7 (Berkeley) 5/16/90";
#endif /* LIBC_SCCS and not lint */

#include <string.h>
#include <sys/types.h>

/*
* sizeof(word) MUST BE A POWER OF TWO
* SO THAT wmask BELOW IS ALL ONES
*/
typedef int word; /* "word" used for optimal copy speed */

#define wsize sizeof(word)
#define wmask (wsize - 1)

/*
* Copy a block of memory, handling overlap.
* This is the routine that actually implements
* (the portable versions of) bcopy, memcpy, and memmove.
*/
void bcopy(const void *src0, void *dst0, size_t length)
//void bcopy( src0, dst0, length)
char *dst0;
char *src0;
register size_t length;
{
register char *dst = dst0;
register char *src = src0;
register size_t t;

if (length == 0 || dst == src) /* nothing to do */
return;

/*
* Macros: loop-t-times; and loop-t-times, t>0
*/
#define TLOOP(s) if (t) TLOOP1(s)
#define TLOOP1(s) do { s; } while (--t)

if ((unsigned long)dst < (unsigned long)src) {
/*
* Copy forward.
*/
t = (int)src; /* only need low bits */
if ((t | (int)dst) & wmask) {
/*
* Try to align operands. This cannot be done
* unless the low bits match.
*/
if ((t ^ (int)dst) & wmask || length < wsize)
t = length;
else
t = wsize - (t & wmask);
length -= t;
TLOOP1(*dst++ = *src++);
}
/*
* Copy whole words, then mop up any trailing bytes.
*/
t = length / wsize;
TLOOP(*(word *)dst = *(word *)src; src += wsize; dst += wsize);
t = length & wmask;
TLOOP(*dst++ = *src++);
} else {
/*
* Copy backwards. Otherwise essentially the same.
* Alignment works as before, except that it takes
* (t&wmask) bytes to align, not wsize-(t&wmask).
*/
src += length;
dst += length;
t = (int)src;
if ((t | (int)dst) & wmask) {
if ((t ^ (int)dst) & wmask || length <= wsize)
t = length;
else
t &= wmask;
length -= t;
TLOOP1(*--dst = *--src);
}
t = length / wsize;
TLOOP(src -= wsize; dst -= wsize; *(word *)dst = *(word *)src);
t = length & wmask;
TLOOP(*--dst = *--src);
}
return;
}

[lisati]

Moved to "Programming Talk"

[Compyx]

Hi, i am using a tool developed in C and i use "make all" command to run. But the following error occur:

cc -O -DUNIX -DBSD -g -I/home/English/morph-1.5/hash -I/usr/include/X11/Xaw -c -w -o lib/bcopy.o /home/English/morph-1.5/hash/bcopy.c
/home/English/morph-1.5/hash/bcopy.c: In function ‘bcopy’:
/usr/include/bits/string3.h:90: error: old-style parameter declarations in prototyped function definition
make: *** [lib/bcopy.o] Error 1



void bcopy(const void *src0, void *dst0, size_t length)
//void bcopy( src0, dst0, length)
char *dst0;
char *src0;
register size_t length;
{



That's were the error is occuring, like the message said, old-style (pre-ANSI) parameter declarations mixed with prototyped (ANSI) function definition.
Two quick solutions here: either remove the prototyped definition and uncomment the old-style definition:


//void bcopy(const void *src0, void *dst0, size_t length)
void bcopy( src0, dst0, length)
char *dst0;
char *src0;
register size_t length;
{


or use the new-style prototyped function defintion:


void bcopy(const void *src0, void *dst0, size_t length)
/* void bcopy( src0, dst0, length)
char *dst0;
char *src0;
register size_t length;
*/
{


I would go for the prototyped function definition, unless you need portability to old systems without an ANSI/ISO-C compliant compiler.

Another way is this:


#ifdef __STDC__
void bcopy(const void *src0, void *dst0, size_t length)
#else
void bcopy( src0, dst0, length)
char *dst0;
char *src0;
register size_t length;
#endif
{

This will pick the prototyped version for ANSI/ISO-C compliant compilers and the old definition syntax for pre-ANSI/ISO compilers.

Additional nitpick: C++-style comments (//) are accepted in C99 and GNU-C, but illegal in C90, so if you want maximum portability you should avoid those.


Hope this helps.