passing flags to a function

[Dan McMahill]

Hello,

I'm sure this is a very basic question about passing "or-able" flags to 
a function.  In C I might do something like:

#define FLAG_FOO 1
#define FLAG_BAR 2
#define FLAG_BAZ 4

....

myfn(int flags)
{

   if (flags & FLAG_BAR)
     printf ("bar flag is set\n");

...

}

and then call myfn with things like

myfn(FLAG_FOO | FLAG_BAZ);


now suppose I want to wrap up myfn and make it available from scheme. 
What is the normal scheme way for passing in flags to a function?

I can do something like

SCM scm_myfn(SCM flags)
{

  myfn (scm_num2int (flags, SCM_ARG1, "myfn"));

  return SCM_BOOLEAN_T;

}

but I'm not sure of the best way to define the flags in scheme.  Or 
maybe this is not "the scheme way".

Thanks for any suggestions.

-Dan