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====== C++ ==
===== Guidlines for efficient C/C++ Code ==

  - Pass and return primitives //as value// to and from functions [Breymann] p177 ,[Davis]
  - Pass objects as const reference to functions and omit ''const'' only when the function is designed to modify the object [Breymann] p177
  - Return objects which are attributes of the class as const reference and objects wich are //not// class attributes (especially stack and heap :?: objects) as value!  [Breymann] p177
  - Prefer references to pointers. References (and reference types) are just syntactic sugar for pointers and do not cause runtime overhead [Breymann?], [Quiroz]
  - To avoid memory leaks encapsulate ''new'' and ''delete'' in the constructor and destructor of a class. Than create the instance of the class as automatic variable. [?]
  - Always declare constant primitives and objects with ''const''
  - ''int'' is the most efficient type for local variables. (No filling with zero's necessary) [Davis]
  - Use ''stdint.h''. It offers... [Davis]
    * exact length types
    * smallest types of at least given length and
    * most efficient types
  - Larger data types as ''int'' are less efficient [Davis]
  - Use the ''size_t'' and ''ptdiff_t'' types for memory calculations, not the ''long'' type [Davis]
  - Unsigned types tend to be more efficient then signed [Davis]
  - Plain ''char'' is always the most efficient char type. For signed or unsigned char it depends on the target which one is more efficient. [Davis]
  - Declare global data and functions as ''static'' whenever possible but avoid ''static'' variables at function level whenever possible [Davis]
  - :?: Use the ''restrict'' keyword for data that is modified by one certain pointer [Davis]
  - Declare variables in the innermost scope possible [Davis]
  - Prefer float types to double (Use ''3.0f'' instead of ''3.0'' and ''sinf()'' instead of ''sin()'') [Davis]
  - It most often more efficient to use the stack rather than the heap for variable length arrays. FIXME Expamle! [Davis]
  - Declare a function as inline when it is... [Davis]
    * small
    * called very often from few places (e.g. inside a loop)
  - Use a ''mutex'' for concurrent data access [Obiltschnig]
  - Do not use exceptions in realtime / embedded systems. They may have non-deterministic runtime behauviour. Use [[becki/coding/c#error_reporting_in_functions|goto]] as alternative. [Obiltschnig], [Quiroz]
  - Use consts rather than preprocessor defines [Quiroz]
  - To avoid name collisions use namespaces rather than prefixes or classes [Quiroz]
  - Aviod Run-Time Type Identification (RTTI) at least for  realtime / embedded systems [Quiroz]

===== References ==

| [Breymann] | Ulrich Breymann. C++ Einführung und professionelle Programmierung |
| [Davis] | Greg Davis. Guidlines for efficient C/C++ Code. Lecture at the "Embedded Systems" fair in Nuremberg 2009-03-04 |
| [Obiltschnig] | Günter Obiltschnig. C++ for Safety-critical Systems. Lecture at the "Embedded Systems" fair in Nuremberg 2009-03-04 |
| [Quiroz] | César A Quiroz. Using C++ Efficiently In Embedded Applications. Mentor Graphics, Embedded Software Division |
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