Common Errors and How To Avoid Them

For comparisons of signed and unsigned variables, the problem is most often that you incorrectly used an int when you should have used Size, per our conventions.
- If you need a negative number, you still should not be using int; use SSize.
- If you don't fix the root problem, you can always cast, but in that case, follow the conventions and use static_cast<int>(), not (int)().
The default initialization of a char: char foo = char(0), which is the same as char foo = char().

To "unhide" a virtual overloaded function, use using to add the original function to the scope of the derived class:

class parent {
public:
    void foo(int);
};

class child : public parent {
public:
    using parent::foo;

    void foo(float);
};

To fix an unused parameter warning, simply remove the variable name from the declaration:
```
void foo(char bar);
```
to:
```
void foo(char /*bar*/);
```
or (better, if you never intend to use bar in the implementation of foo):
```
void foo(char);
```

39737bef0814ff5f067e725d7984346053b2f888

To compare a "non-pointer" with NULL, use get() on the OP.

To avoid "foo will be initiallized after bar" warnings, initialize in the same order as the private data is listed in the .hh file.
If you can't use core::Size to fix a type comparison warning (because you are lower than core), use platform::Size instead.

Code like this:

foo = R"bar(
        var1, var2
    )";

should be changed to this:

foo = "bar(\n"
    "    var1, var2\n"
    ")";

To fix ignoring return value of 'int foo(bar)', declared with attribute warn_unused_result [-Wunused-result] surround the function with an if block, e.g.:
```
if (system(command_line.c_str()) == -1) {
    TR.Error << "Shell command failed to run!" << std::endl;
}
```

Use preprocessor directives — such as #ifndef NDEBUG or #ifdef PYROSETTA to enable code to only be used in certain compile modes. This allows one to avoid unused variable warnings that only occur in certain build modes. For example, the following code avoids an unused parameter warning and functions differently if Python is available:

void
PhenixInterface::setAlgorithm(
#ifdef WITH_PYTHON
        std::string algo)
#else
        std::string /*algo*/)
#endif
{
#ifdef WITH_PYTHON
    algo_ = algo;

    // nuke the target evaluator
    if (target_evaluator_) {
        Py_DECREF(target_evaluator_);
        target_evaluator_ = NULL;
    }
#else
    utility_exit_with_message( "ERROR!  To use crystal refinement compile Rosetta with extras=python." );
#endif
}

void* functions throw no return statement in function returning non-void [-Wreturn-type] warnings. void* is a pointer to a function that returns void. Since we have no function to return, return a NULL pointer.
chars cannot be appended to strings with +. To append a char to a string, you must cast it first. (I suggest using std::string(1, my_char).)
ints cannot be appended to strings with + either. To append an int to a string, you must cast it first. (I suggest using boost::lexical_cast<std::string)(my_int).)

Common Errors and How To Avoid Them

See Also