fgetspent_r
extern struct spwd *fgetspent_r(FILE *, struct spwd *, char *, int);
fgetspent_r(f, b->result, b->buffer, b->buflen));
while (!found && fgetspent_r(fp, result, buffer, buflen) != NULL) {
while (fgetspent_r(src, &cur, buf, sizeof (buf)) != NULL) {