_readbufline
extern int _readbufline(char *, int, char *, int, int *);
extern int _readbufline(char *, int, char *, int, int *);
linelen = _readbufline(exec_f_buf, f_size, instr, be->minbuf,
extern int _readbufline(char *, int, char *, int, int *);