[Pgubook-readers] debug problem "with no line number"

[harold]

hi,all
I am a reader of pgubook.
I encounted a problem when I read on the chapter 6.In
the section "Writing records",there are
two files:"write-records.s" and "write-record.s".
I run the commands for debug later:
as --gstabs write-records.s -o write-record.o
as --gstabs write-record.s -o write-record.o
ld write-records.o write-record.o -o write-records
and ./write-records
there is no error.but the problem is that I attempt to
debug the program with gdb and emacs.
when i typed this command:
gdb write-records

below is the messages
(gdb) break 64
Breakpoint 1 at 0x8049467: file write-records.s, line
64.
(gdb) run
Starting program: /home/harold/asm/write-records

Breakpoint 1, 0x08049467 in _start ()
(gdb) s
Single stepping until exit from function _start,
which has no line number information.
write_record () at write-record.s:17
17        pushl %ebp
Current language:  auto; currently asm

I don't understand this line "Single stepping until
exit from function _start,
which has no line number information."

other programs is ok.I can't find any errors.
Can anybody help me!!!


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