/*
\funcref{xstrcat}{char $*$xstrcat (\params)}
    {
        {char} {*s1} {reallocatable string to cat to}
        {char} {*s2} {string to cat to {\em s1}}
    }
    {reallocated string {\em s1} with {\em s2} concatenated to it}
    {xrealloc()}
    {xstrdup()}
    {xstrcat.c}
    {

        Function {\em xstrcat()} reallocates the string {\em s1} and then
        concatenates {\em s2} to it. Therefore, the first argument of the
        function must point to allocated memory. The second argument may be any
        string, and can possibly be freed after the call.

    }
*/

#include "icrssdef.h"

char *xstrcat (s1, s2)
char *s1, *s2;
{
    register unsigned
        s1len;

    if (! s1 || ! *s1)
        return (xstrdup (s2));
    if (! s2 || ! *s2)
        return (xstrdup (s1));

    s1len = strlen (s1);
    s1 = xrealloc (s1, strlen (s1) + strlen (s2) + 1);
    strcat (s1, s2);
    return (s1);
}