function parameter guideline

standards/cpp.md

@@ -1,15 +1,51 @@
-# C++
+# C/C++
 
-The c++ code should focus on using simplicity over "modern solutions". This may often mean to restrict the code on earlier c++ versions and sometimes even c code.
+The C/C++ code should focus on using simplicity over "modern solutions". This may often mean to heavily restrict the code. The following rule of thumb applies:
+
+1. C24 should be used where reasonable (large parts of the cOMS framework)
+2. C++ may be used in places where external libraries basically require C++
+
+The reason for the strong focus on C is that we **personally** believe that C is simpler and easier to understand than the various abstractions provided by C++.
 
 ## Operating system support
 
-C++ solutions must be valid on Windows 10 and Linux.
+C/C++ solutions must be valid on Windows 10+ and Linux.
 
-## Use of namespace
+## Namespace
+
+### use
 
 Namespaces must never be globally used. This means for example `use namespace std;` is prohibited and functions from the standard namespace should be prefixed instead `std::`
 
+### Code structuring
+
+It is encouraged to use C++ namespaces to structure code. In C programmers often use prefixes to more or less re-create namespaces. We consider this a hack and advocate for C++ namespaces.
+
+```cpp
+namespace Your::Name::Space {
+
+}
+```
+
 ## Templates
 
-Don't use c++ templates.
+Don't use C++ templates.
+
+## Allocation
+
+Use C allocation methods for heap allocation.
+
+## C++ function
+
+Don't use C++ standard functions or C++ functions provided by other C++ header files unless you have to work with C++ types which is often required when working with third party libraries.
+
+## Modifying vs. returning
+
+Generally, functions that thake pointers to non-scalar types should modify the data instead of allocating new memory **IF** reasonable. This forces programmers to consciously create copies before passing data **IF** they need the original data. To indicate that a reference/pointer is not modified by a function define them as const!
+
+We believe this approach provides a framework for better memory management and better performance in general.
+
+Examples for this can be:
+
+* Matrix multiplication with a scalar
+* Sorting data (depends on sorting algorithm)