inclusion guard is something like
#ifndef MYFILE_H
#define MYFILE_H
...
#endif
that makes it so the header won't be included more than once.
Thanks,
Tyler Littlefield
http://tds-solutions.net
Twitter: sorressean
On Jan 24, 2010, at 6:50 PM, Jimmy Johnson wrote:
> Not sure what you mean by include guards? Is this the "if not defined include
> it" constructs?
>
> If so then when I write a class I must do something like:
>
> if not defined GL then {include <GL.h> define GL?
>
> I'm not sure of the syntax yet, but if that is the process, then every class
> I write will have to know that *I* am using the symbol "GL"?
>
> But let's say I am writing a class that may be used in many projects,
> would/should I say at the top of my file something like:
> #define MYFILE_INCLUDED // let users know that my header has been used and
> they can check for this symbol MYFILE_INCLUDED?
>
> (I know this must seem basic, but I come from an environment which takes care
> of all of this for you.)
>
> --- In [email protected], Paul Herring <pauljherr...@...> wrote:
> >
> > On Mon, Jan 25, 2010 at 1:23 AM, Jimmy Johnson <boxer...@...> wrote:
> > > I have a file myClass.h which defines an interface. The definition
> > > depends on no other classes [headers].
> > >
> > > The implementation of the member functions for myClass in the cpp file
> > > uses openGL calls so I must include <gl.h>. (I use a c-wrapper in my
> > > main() to get the correct function type for the c++ objects.)
> > > Where should I put the #include <gl.h>, in the header file or the cpp
> > > file?
> >
> > Does your header file require anything from <gl.h>? If so, put it in
> > your header file; if not put it in the cpp file.
> >
> > > In my [c-like] main [or root] program I include #myClass.h, but I the
> > > main also uses glut so I must include
> > > <glut.h>, which itself includes <gl.h>. Have I included gl.h twice?
> >
> > Yes (presuming glut.h is your header file,) but the contents of that
> > file will (should) only be parsed once.
> >
> > > Is this bad?
> >
> > Not necessarily.
> >
> > >If so how do you account for this?
> >
> > <gl.h> should have include guards to prevent it being parsed more than once.
> >
> >
> > --
> > PJH
> >
> > http://shabbleland.myminicity.com/
> > http://www.chavgangs.com/register.php?referer=9375
> > http://www.kongregate.com/?referrer=Shabble
> >
>
>
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