Re: [Valgrind-users] suppress warning repetition

[João M. S. S. <joa...@gm...>]

> Tom Hughes' suggestion to fix the invalid file descriptor first is
> valid.  A memory overwrite can cause all kinds of problems (what if you
> overwrote 1 million characters of the buffer?) and many of the results
> afterward will be unreliable.  Your program may appear to run correctly
> once, but it is a disaster waiting to happen.

The invalid file descriptor comes from this buffer overrun. Writing 
after the command buffer overwrites the file descriptor value. I've 
fixed it by using C++ strings, since there are no performance issues 
from that specific line.

> The procedure for cleaning up a program is to fix all of the problems
> you know how to fix, then rerun valgrind.  Repeat until all errors are
> gone.  Errors late in a program's run may have been caused by earlier
> errors.  New errors may appear after you fix the initial set of
> problems; they were simply masked by the previous errors.

Yes, I normally do that. I have 0 errors and 0 warnings from gcc with a 
reasonable set of switches: -Wall, -Wextra, -Wpedantic. Then I run 
cppcheck with 0 errors/warnings. Then valgrind with 0 memory errors, and 
from time to time eliminate all leaks. There are only leaks from other 
libraries.

> You are on the right track; you need to keep at it.  There have been
> times when I've had so many problems in so many places that I simply
> fixed the first one and reran valgrind.  In your case, the "bad file
> descriptor" error was a symptom of another problem, not a cause. Once
> you fix that you can move on to any other problems that may appear.

Yes, I remember when I first wrote a C program (back in 1995) and got 
more than one hundred errors and despaired. Then I fixed one bracket and 
almost all of them were gone :) At that time we used pico in a 
monochrome terminal :P I miss that "ASCII" feeling :)

-- 
João M. S. Silva