redirecting output

redirecting output

[Per Fransson]

Hi,

I'm trying to log a whole lot of program counter values during the
execution of a program using GDB on sparc (solaris-2.8). I'm doing it with
a command file like this one:

b <point early in the program>
run
si
si
si
.
.
'bout a million si's
.
.
.
si
si
q


Then I run it like this:

% gdb a.out --command=command_file > pc_log


Unfortunately it doesn't seem to work. Somehow the execution gets
corrupted. The 'pc_log' file deviates from what I get by just letting gdb
print to stdout like this (they come to different concusions at some
conditional branch):

% gdb a.out --command=command_file


I find this very puzzling. Can someone tell me what's going on? And,
better yet, how I can get the pc log I'm looking for?

Thanks in advance

Per

Re: redirecting output

[Eli Zaretskii]

On Mon, 25 Nov 2002, Per Fransson wrote:

> % gdb a.out --command=command_file > pc_log
> 
> 
> Unfortunately it doesn't seem to work. Somehow the execution gets
> corrupted. The 'pc_log' file deviates from what I get by just letting gdb
> print to stdout like this (they come to different concusions at some
> conditional branch):
> 
> % gdb a.out --command=command_file
> 
> 
> I find this very puzzling. Can someone tell me what's going on? And,
> better yet, how I can get the pc log I'm looking for?

The best technique as of now is to use the `script' command (assuming you 
are on a Posix host) or some work-alike.

Adding a feature you would like to have is a long-standing TODO item in 
GDB development.

Re: redirecting output

[Ben Elliston]

>>>>> "Per" == Per Fransson <fransson@cs.lth.se> writes:

  Per> b <point early in the program>
  Per> run
  Per> si
  Per> si
  Per> si
  Per> .
  Per> .
  Per> 'bout a million si's
  Per> .
  Per> .
  Per> .
  Per> si
  Per> si
  Per> q

BTW, it is not necessary to print about a million si'.s You can run
"si" inside a while loop.  From memory, the while loop will terminate
when the program terminates.

Ben