C++ for Scientists - Technische Universität Dresden

10.3. VALGRIND 239
Stepi and Nexti This are the equivalents on instruction level. This is
only needed for debugging assembler code and not subject in this
book.
Until Position your cursor in your source and run the program until you
reach this line. If your program flow do not pass this line the execution
will continued till the end, the next break point or bug.
Finish Execute the remainder of the current function and stop in the first
line outside this function, i.e. the line after the function call.
Cont Continue your execution till the next event (break point, bug, or
end).
Kill the program.
Up Show the line of the current function’s call, i.e. go up one level in the
call stack.
Down Go back to the called function, i.e. go down one level in the call
stack.
Undo Revert last action (works rarely or never).
Redo Repeat the last command.
Edit Call an editor with the source file currently shown.
Make Call ‘make’ (which must know what to compile).
10.3 Valgrind
The valgrind distribution offers several tools that you can use to analyze your software. We will
only use one of these tools called memcheck. For more information on the others we refer you
to http://valgrind.org Memcheck detects memory-management problems like memory leaks.
Memcheck also reports if your program accesses memory it should not or if it uses uninitialized
values. All these errors are reported as soon as they occur along with the corresponding source
line number at which they occurred and also a stack trace of the functions called to reach
that line. You should also take into account that Memcheck runs programs about 10 to 30
times slower than normal. Use the following command to check the memory management of a
program:
valgrind −−tool=memcheck program name
10.4 Gnuplot
A useful tool for making plots is Gnuplot. It is a public domain program.
Invoke gnuplot to start the program. Suppose we have the file results with the following
content: