c vs cc vs cpp vs hpp vs h vs cxx

Question

Possible Duplicates    h or   hpp for your class definitions Correct C   code file extension   cc vs  cpp   I used to think that it used to be that    h files are header files for C and C    and usually only contain declarations   c files are C source code   cpp files are C   source code  which can also be C source code    then files like  hpp   cc  and  cxx came along  and I got totally confused    what s the difference s  between those  When do you use the  quot new quot  ones

User · Accepted Answer

Historically  the first extensions used for C   were  c and  h  exactly like for C   This caused practical problems  especially the  c which didn t allow build systems to easily differentiate C   and C files   Unix  on which C   has been developed  has case sensitive file systems   So some used  C for C   files   Other used  c     cc and  cxx    C and  c   have the problem that they aren t available on other file systems and their use quickly dropped  DOS and Windows C   compilers tended to use  cpp  and some of them make the choice difficult  if not impossible  to configure   Portability consideration made that choice the most common  even outside MS-Windows   Headers have used the corresponding  H   h     hh   hxx and  hpp  But unlike the main files   h remains to this day a popular choice for C   even with the disadvantage that it doesn t allow to know if the header can be included in C context or not  Standard headers now have no extension at all   Additionally  some are using  ii   ixx   ipp   inl for headers providing inline definitions and  txx   tpp and  tpl for template definitions   Those are either included in the headers providing the definition  or manually in the contexts where they are needed   Compilers and tools usually don t care about what extensions are used  but using an extension that they associate with C   prevents the need to track out how to configure them so they correctly recognize the language used   2017 edit  the experimental module support of Visual Studio recognize  ixx as a default extension for module interfaces  clang   is recognizing  c  m   cppm and  cxxm for the same purpose

User · Answer

It really doesn t matter  If you feed  c to a c   compiler it will compile as cpp   cc  cxx is just an alternative to  cpp used by some compilers    hpp is an attempt to distinguish header files where there are significant c and c   differences   A common usage is for the  hpp to have the necessary cpp wrappers or namespace  and then include the  h  in order to expose a c library to both c and c

User · Answer

I use   hpp  for C   headers and   h  for C language headers  The   hpp  reminds me that the file contains statements for the C   language which are not valid for the C language  such as  class  declarations

User · Answer

Generally   c and  h files are for C or C-compatible code  everything else is C     Many folks prefer to use a consistent pairing for C   files   cpp with  hpp   cxx with  hxx   cc with  hh  etc   My personal preference is for  cpp and  hpp

User · Answer

Talking about  hpp extension  I find it useful when people are supposed to know that this header file contains C   an not C  like using namespaces or template etc  by the moment they see the files  so they won t try to feed it to a C compiler  And I also like to name header files which contain not only declarations but implementations as well  as  hpp files  like header files including template classes  Although that s just my opinion and of course it s not supposed to be right

User · Answer

Those extensions aren t really new  they are old   -   When C   was new  some people wanted to have a  c   extension for the source files  but that didn t work on most file systems  So they tried something close to that  like  cxx  or  cpp instead   Others thought about the language name  and  incrementing   c to get  cc or even  C in some cases  Didn t catch on that much   Some believed that if the source is  cpp  the headers ought to be  hpp to match  Moderately successful

[c++] .c vs .cc vs. .cpp vs .hpp vs .h vs .cxx

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