strxcat.c

Many C samples. It is a good sample for students to learn C language.

/*  File   : strxcat.c
    Author : Richard A. O'Keefe.
    Updated: 25 may 1984
    Defines: strxcat()

    strxcat(dst, src1, ..., srcn, NullS)
    moves the concatenation of dst,src1,...,srcn to dst, terminates it
    with a NUL character, and returns the original value of dst.
    It is just like strcat except that it concatenates multiple sources.
    Equivalence: strxcat(d, s1, ..., sn) <=> strxcpy(d, d, s1, ..., sn).
    Beware: the last argument should be the null character pointer.
    Take VERY great care not to omit it!  Also be careful to use NullS
    and NOT to use 0, as on some machines 0 is not the same size as a
    character pointer, or not the same bit pattern as NullS.
*/

#include "strings.h"
#include <varargs.h>

/*VARARGS*/
char *strxcat(va_alist)
    va_dcl
    {
	va_list pvar;
	register char *dst, *src;
	char *bogus;

	va_start(pvar);
	dst = va_arg(pvar, char *);
	bogus = dst;
	while (*dst) dst++;
	src = va_arg(pvar, char *);
	while (src != NullS) {
	    while (*dst++ = *src++) ;
	    dst--;
	    src = va_arg(pvar, char *);
	}
	return bogus;
    }