No symbol table is loaded. Use the "file" command. --- new to gdb: please help !

No symbol table is loaded. Use the "file" command. --- new to gdb: please help !

[Grazia Russo-Lassner]

hello,

I am trying to debug a program, but when I enter a breakpoint I get
No symbol table is loaded.  Use the "file" command.

This is what I do:
gdb filename-of-executable
break 48	#to break at line 48

then I get:
No symbol table is loaded.  Use the "file" command.

Could someone help ?

Thank you in advance.

Grazia

Re: No symbol table is loaded. Use the "file" command. --- new to gdb: please help !

[Daniel Jacobowitz]

On Fri, Dec 09, 2005 at 04:48:13PM -0500, Grazia Russo-Lassner wrote:
> 
> hello,
> 
> I am trying to debug a program, but when I enter a breakpoint I get
> No symbol table is loaded.  Use the "file" command.
> 
> This is what I do:
> gdb filename-of-executable
> break 48	#to break at line 48
> 
> then I get:
> No symbol table is loaded.  Use the "file" command.
> 
> Could someone help ?

Probably your binary does not contain debug information.  Try
recompiling with -g.

-- 
Daniel Jacobowitz
CodeSourcery, LLC

Re: No symbol table is loaded. Use the "file" command. --- new to gdb: please help !

[Grazia Russo-Lassner]

thank you, Daniel.
It works now.

g.

================================================================

Grazia Russo-Lassner

Dept. of Linguistics and Institute of Advanced Computer Studies, 
University of Maryland, College Park, MD 20742
e-mail : glassner@umiacs.umd.edu
phone  : 301 405 6746

===============================================================

On Fri, 9 Dec 2005, Daniel Jacobowitz wrote:

> On Fri, Dec 09, 2005 at 04:48:13PM -0500, Grazia Russo-Lassner wrote:
>>
>> hello,
>>
>> I am trying to debug a program, but when I enter a breakpoint I get
>> No symbol table is loaded.  Use the "file" command.
>>
>> This is what I do:
>> gdb filename-of-executable
>> break 48	#to break at line 48
>>
>> then I get:
>> No symbol table is loaded.  Use the "file" command.
>>
>> Could someone help ?
>
> Probably your binary does not contain debug information.  Try
> recompiling with -g.
>
> -- 
> Daniel Jacobowitz
> CodeSourcery, LLC
>

how to debug functions called from other classes

[Grazia Russo-Lassner]

Hi,

the function BuildVcb is where the error message of my code comes from:

line50 : parser->BuildVcb(arg1, arg2);

But BuildVcb is actually a function implemented in a separate class.
Thus, when I use the gdb commands (run, next, step, where, etc.) I end up 
executing the function without being able to go step by step inside BuildVcb.
What gdb commands should I use ?
I would very much appreciate if someone could help, I am a novice in gdb.

thank you,

grazia

Re: how to debug functions called from other classes

[Jim Blandy]

On 12/10/05, Grazia Russo-Lassner <glassner@umiacs.umd.edu> wrote:
> the function BuildVcb is where the error message of my code comes from:
>
> line50 : parser->BuildVcb(arg1, arg2);

So, 'BuildVcb' is a method of whatever class 'parser' points to; and
when you call 'parser->BuildVcb', that code prints an error message;
is that right?

What does GDB do when you reach line 50 and type 'step' to step into
the method call?  Can you show us a transcript?

Re: how to debug functions called from other classes

[Grazia Russo-Lassner]

Hello Jim,


On Sat, 10 Dec 2005, Jim Blandy wrote:

> On 12/10/05, Grazia Russo-Lassner <glassner@umiacs.umd.edu> wrote:
>> the function BuildVcb is where the error message of my code comes from:
>>
>> line50 : parser->BuildVcb(arg1, arg2);
>
> So, 'BuildVcb' is a method of whatever class 'parser' points to; and
> when you call 'parser->BuildVcb', that code prints an error message;
> is that right?

 	the code exits  and  prints out the error message that was
 	coded 	in that function.
 	I know it has to do with the input file to that function,
 	BuildVcb.
 	I cannot pinpoint the input line that is breaking the code.

 	grazia
>
> What does GDB do when you reach line 50 and type 'step' to step into
> the method call?  Can you show us a transcript?
>

Re: how to debug functions called from other classes

[Grazia Russo-Lassner]

Jim,
my question is how tobe able to step into BuildVcb.
So far when I "step" the entire output of BuildVcb gets printed out.

G.

On Sat, 10 Dec 2005, Jim Blandy wrote:

> On 12/10/05, Grazia Russo-Lassner <glassner@umiacs.umd.edu> wrote:
>> the function BuildVcb is where the error message of my code comes from:
>>
>> line50 : parser->BuildVcb(arg1, arg2);
>
> So, 'BuildVcb' is a method of whatever class 'parser' points to; and
> when you call 'parser->BuildVcb', that code prints an error message;
> is that right?
>
> What does GDB do when you reach line 50 and type 'step' to step into
> the method call?  Can you show us a transcript?
>

Re: how to debug functions called from other classes

[Jim Blandy]

On 12/11/05, Grazia Russo-Lassner <glassner@umiacs.umd.edu> wrote:
> my question is how tobe able to step into BuildVcb.
> So far when I "step" the entire output of BuildVcb gets printed out.

So, when the program reaches the line containing the call of the
BuildVcb method, and you type "step", GDB acts as if you had typed
"next" or "continue"?

If you ask GDB to "step" into a function or method that has no
debugging information, GDB will do a "next" instead.  Did you compile
the file that contains the definition of the BuildVcb method with -g?

Re: how to debug functions called from other classes

[Grazia Russo-Lassner]

thank you, Jim.
i am able to step into the function now.

Grazia


On Sun, 11 Dec 2005, Jim Blandy wrote:

> On 12/11/05, Grazia Russo-Lassner <glassner@umiacs.umd.edu> wrote:
>> my question is how tobe able to step into BuildVcb.
>> So far when I "step" the entire output of BuildVcb gets printed out.
>
> So, when the program reaches the line containing the call of the
> BuildVcb method, and you type "step", GDB acts as if you had typed
> "next" or "continue"?
>
> If you ask GDB to "step" into a function or method that has no
> debugging information, GDB will do a "next" instead.  Did you compile
> the file that contains the definition of the BuildVcb method with -g?
>