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RE: What is a good profiling tool ? - problem with gprof

-----Original Message-----
Subject: Re: What is a good profiling tool ? - problem with gprof

On Jun 18 12:11, Corinna Vinschen wrote:
> On Jun 17 12:52, Larry Hall (Cygwin) wrote:
> > On 6/17/2013 12:19 PM, J.B.W.Webber wrote:
> > >Hi, I am trying to find in which function call the most time is being spent.
> > >
> > >I am using gcc and trying to compile and link with -g and -pg.
> > >i.e. for a trivial test :
> > >
> > >$ cat helloworld.c
> > >/* Hello World program */
> > >#include<stdio.h>
> > >main()
> > >{
> > >     printf("Hello World\n");
> > >}
> > >
> > >$ gcc -g -pg -c helloworld.c
> > >$ gcc -pg helloworld.o
> > >helloworld.o: In function `main':
> > >helloworld.c:6: undefined reference to `_mcount'
> > >collect2: ld returned 1 exit status
> > >
> > >Any ideas ? Am I missing a .h call ? Or do I need to link to something ?
> > 
> > Worked for me.  Perhaps your Strawberry gcc installation is interfering.
> I don't know how you succeeed to build that, Larry.  I could easily 
> reproduce the problem.  It was a build problem in Cygwin.  I fixed 
> that now and at the same time made the 64 bit profiling workable, 
> curtesy the
> Mingw-w64 project, which already did the required work.  The original 
> profiling code was created within the Cygwin project ages ago, so I 
> could included the latest Mingw-w64 profiling code (almost) verbatim 
> into Cygwin and now it seems to work fine again for 32 and 64 bit.
> I'm just about to create a 2013-06-18 32 bit snapshot on 
> and a 64 bit test release 1.7.12-5, which 
> both should be ready in an hour.

Uploaded.  Please note that it's *not* enough to install the snapshot Cygwin DLL.  The important items here are gcrt0.o and libgmon.a.


Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat


Really thanks to all. That now works.

Sorry for the slow reply, I did the install with the snapshot as suggested 
- no difference, at first, but I had been given the clues I needed.

I used find to track all libgmon.a  on my laptop :


I blocked access to the Altera and Strawberry Cygwins, which made no difference, (no, XMOS does not use Cygwin)
But the answer was the version C:/cygwin/lib/libgmon.a
I copied the new gcrt0.o and libgmon.a into C:/cygwin/lib/
and all now works fine. I have the answer I needed.

I do thank you all,

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