Hi Padraig,
What is the exact error message you get?
Are you compiling on a 64-bit machine?
I believe I have the following (simplyfied) code:
off_t a;
size_t b;
off_t c;
if (a + (off_t) b > c)
c = a + (off_t) b;
And the line "if (a + (off_t) b > c)" is generating the warning.
Maybe you can confirm this, with this simple example.
On Nov 11, 2009, at 3:22 PM, Padraig O'Sullivan wrote:
On Wed, Nov 11, 2009 at 9:07 AM, Paul McCullagh
<[email protected]> wrote:
Hi Padraig,
On Nov 11, 2009, at 2:56 PM, Padraig O'Sullivan wrote:
Just one change I am not sure of:
datalog_xt.cc: line 1206
#ifdef DEBUG
if (dlb_buffer_offset + (xtLogOffset)
dlb_buffer_len >
dlb_max_write_offset)
dlb_max_write_offset = dlb_buffer_offset +
(xtLogOffset) dlb_buffer_len;
#endif
-->
#ifdef DEBUG
if (dlb_buffer_offset + dlb_buffer_len >
dlb_max_write_offset)
dlb_max_write_offset = dlb_buffer_offset +
(xtLogOffset) dlb_buffer_len;
#endif
This is a case of "off_t + size_t > off_t".
The size_t was cast to an off_t in case size_t is 4 bytes and
off_t is 8.
So we want to make sure that the calculation is done using 8 byte
values
in
this case.
Did you get a warning on this line? Maybe due to signed to unsigned
conversion?
Sorry, that's my bad. I meant to revert that change before
commiting.
Yes, I had gotten a warning to do with comparison of signed and
unsigned integers in a few places in that file. I was going to try
and
fix those warnings but then decided it would be better to not do
that
and just updated the compiler flags to include -Wno-sign-compare
instead.
Turning the warning off is a quick solution, but I would really
like to know
how to write this code so that all compilers are happy!
I have no problem with changing the code, but I don't want to
change it,
just to run into a warning on some other system.
Ah, ok. I didn't change anything as I wasn't sure if things were done
like that for a certain reason or not. The warning pops up in quite a
few places in that file for me when I compile with debug symbols.
In particular, I am wondering why the compiler is generating a
warning in
this case where we have an explicit conversion?
I'm not sure either and would be interested in learning if someone
could provide an answer.
Any ideas?
--
Paul McCullagh
PrimeBase Technologies
www.primebase.org
www.blobstreaming.org
pbxt.blogspot.com
--
Paul McCullagh
PrimeBase Technologies
www.primebase.org
www.blobstreaming.org
pbxt.blogspot.com
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