Re: accessing a library

From:

"Ben Voigt [C++ MVP]" <rbv@nospam.nospam>

Newsgroups:

microsoft.public.vc.mfc,microsoft.public.vc.language

Date:

Wed, 23 Apr 2008 08:03:03 -0500

Message-ID:

<eq2xwHUpIHA.5096@TK2MSFTNGP02.phx.gbl>

Carmen Sei wrote:

On Tue, 22 Apr 2008 20:41:05 -0400, "Scott McPhillips [MVP]"
<org-dot-mvps-at-scottmcp> wrote:

"Carmen Sei" <fatwallet951@yahoo.com> wrote in message
news:840t04hkt981lmnl808kdiegne38hv9jhs@4ax.com...

Java doesn't follow the deep chian like C++ include header files
does. If you import a java library like java.io.InputStream, you
will have access to InputStream only and doesn't have C++'s chain
header files.

Does C++ programmer found the include chain is hard to manage once
the source base grows big? and most of time, one needs to dig into
the header file like 3 level up to find the object/variable is
defined.

In Visual Studio you can right-click on a variable and select 'Go To
Definition.' No need to dig into a chain of header files.

Your terminology is not quite appropriate for C++. Header files are
not about libraries, they are more general than that. They are
about other code modules of any kind. Sometimes those code modules
are part of the program in cpp files, other times they are in DLLs,
other times they are in a library.

And header files are not about inheritance. They simply declare the
existence of other items so the compiler will know their type.

if main.cpp make use of the all 4 header files, should I include all 4
header files again in main.cpp to remind others that it has used
objects defined in those 4 header files?

Yes, main.cpp should generally #include each header that it *directly* uses,
unless the documentation for the class or function specifically indicates
otherwise.

for example in main.cpp
// inclde the 4 header again
#include Demo.h
#include Config.h
#include Gconfig.h
#include ConfigDef.h

for example in Demo.h
#include Config.h

for example in Config.h
#include GConfig.h

Then I don't need to dig in the chain of includes and it shows more
clean way on which header you used in a .cpp file. wh ich works
similar to java import.

main.cpp -> Demo.h -> Config.h -> Gconfig.h -> ConfigDef.h

the above shows main.cpp include -> Demo.h and Demo.h include ->
Config.h ... and so on