> 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 ------------------------------------------------------------------------------ Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net _______________________________________________ Valgrind-users mailing list Valgrind-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/valgrind-users
