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DragonFly users List (threaded) for 2005-11
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Re: Is debug enabled in userland?

From: walt <wa1ter@xxxxxxxxxxxxx>
Date: Wed, 23 Nov 2005 17:00:46 -0800

On Wed, 23 Nov 2005, ochronus@xxxxxx wrote:

> Hi all,
> I just compiled a debug-disabled 1.3.7 preview kernel, and I wonder if the
> userland has debug enabled...

I'll answer your question because I don't know the answer ;o)  If my answer
is wrong I will *quickly* learn something valuable.

There are (at least) two (completely different) aspects to debugging.  A
developer may include extra debugging code with his application, but this
extra code is normally *ignored* unless you, the user, does something
special while you are compiling the apllication -- e.g. you purposely
type 'make DEBUG_FOO_BAR=yes' or 'make -DDEBUG_FOO_BAR'.  The extra code
you invoke by doing this may slow down your system or cause lots of extra
messages to be written to log files, etc.  (It costs you something.)

The second kind of debugging is very different.  If you compile programs
using the -g compiler flag, the resulting executables will be a bit bigger
because the 'debugging symbols' will be included as part of the final
executable file.  This does *not* slow down your system because *no* extra
code is executed while the program is running.  The only cost to you is a
bit of extra disk space, which is cheap these days.

One more interesting note:  every new kernel you compile will have the
debugging symbols included.  This makes the kernel file (/kernel) bigger,
but not slower.  The next time you compile a new kernel, the old kernel
will be stripped of the debugging symbols and stored as /kernel.old.
This makes /kernel.old smaller than the new /kernel, but has nothing
to do with speed of execution.

As far as I know, DragonFly Userland (like most any other code) does
*not* include extra debugging code unless you take extraordinary
steps to invoke it by using extra command-line flags at compile

If anything I've said is wrong, I would be happy if someone would set
me straight.  Please!  (And thank you ;o)

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