Follow up on __cyg_ ... functions

[Bill Mahoney]

Brian:

Thanks for the reply - I appreciate it.

This much I knew. However! Let me rephrase my question. Suppose I 
compile something with -finstrument-functions and don't supply my own 
function. The linker must resolve it to something, so I assumed that 
there is an empty function (e.g. a "ret" with a global label on it) 
somewhere in the runtime library source; otherwise "ld" would barf. Is 
this not the case, and the linker is just supplying that silently, or what?

The reason I ask is that a couple of years ago I instrumented blocks as 
well. (I am guilty of not posting these to the GCC community.) So I also 
have __cyg_profile_block as an additional extern. I wanted to supply a 
"default, do nothing" function for this as well.

Thoughts?  Thanks again.

Bill


Brian Dessent wrote:
> Bill Mahoney wrote:
>
>   
>> Hey, I would like to know on a new 4.3.2 install, where the source is
>> for the portion of the RT library that contains __cyg_profile_func_enter
>> / _exit.  Can somebody just email me back and aim me at the correct
>> file? I've find/grep'd until my fingers are tired.
>>     
>
> The compiler will insert calls to those functions when you use
> -finstrument-functions but you are meant to provide an implementation of
> them in your own code to receive the data and process it as you wish. 
> So you won't find what you're looking for in gcc anywhere because it
> doesn't exist.
>
> Brian
>   

>