*urlPart = nsCRT::strndup(src + pos, len);
*urlPart = PL_strndup(src + pos, len);
ExtractUrlPart_Helper(const char *src, PRUint32 pos, PRInt32 len,                      PRUint32 *startPos, PRUint32 *endPos, char **urlPart){    if (len < 0) {        if (startPos)            *startPos = 0;        if (endPos)            *endPos = 0;        if (urlPart)            *urlPart = nsnull;    }    else {        if (startPos)            *startPos = pos;        if (endPos)            *endPos = pos + len;        if (urlPart)            *urlPart = nsCRT::strndup(src + pos, len);    }}