Do I need an extern “C” block to include standard POSIX C headers?

by

The system C headers usually already include a extern "C" block, guarded by #ifdef __cplusplus. This way the functions automatically get declared as extern "C" when compiled as C++ and you don’t need to do that manually.

For example on my system unistd.h and fcntl.h start with __BEGIN_DECLS and end with __END_DECLS, which are macros defined in sys/cdefs.h:

/* C++ needs to know that types and declarations are C, not C++.  */
#ifdef   __cplusplus
# define __BEGIN_DECLS  extern "C" {                                            
# define __END_DECLS }
#else
# define __BEGIN_DECLS
# define __END_DECLS
#endif

More Related Contents:

  1. why float and double does not identify 0 in decimal places [duplicate]
  2. Rotating a point about another point (2D)
  3. Print leading zeros with C++ output operator?
  4. How to parse space-separated floats in C++ quickly?
  5. How does generic lambda work in C++14?
  6. “X does not name a type” error in C++
  7. Is right shift undefined behavior if the count is larger than the width of the type?
  8. Why shared_from_this can’t be used in constructor from technical standpoint?
  9. Can we overload operators for built-in types like int or float?
  10. How can I use polymorphic attributes with boost::spirit::qi parsers?
  11. Return a “NULL” object if search result not found
  12. C++ unit testing framework [closed]
  13. Tools to find included headers which are unused? [closed]
  14. Implementing multiple interfaces in c++
  15. Is it possible to determine if a type is a scoped enumeration type?
  16. Inheritance and method overloading
  17. Is there actually a reason why overloaded && and || don’t short circuit?
  18. Difference in behavior while using dynamic_cast with reference and pointers
  19. Order of execution in operator
  20. clean C++ granular friend equivalent? (Answer: Attorney-Client Idiom)
  21. qt thread with movetothread
  22. Create a function to check for key press in Unix using ncurses
  23. C++ Using Class Method as a Function Pointer Type
  24. C++ [Windows] Path to the folder where the executable is located [duplicate]
  25. Why can’t redefine type names in class in C++?
  26. Is it possible to implement lock free map in C++
  27. calling operator
  28. How to create temporary object in C++
  29. C++ copy-construct construct-and-assign question
  30. How do I get at the exception information when using MiniDumpWriteDump out-of-process?

Leave a Comment