[Courses] Absolute Beginning C: void?

[jim]

    As to void for arguments, prototyping is basically 
declaring a function, in my (limited) experience as a 
matter of smoothing the way for functions other than 
main that are in a particular file. 

void myfunc();  
    /* declares myfunc to be a function that takes no 
       arguments and does not return anything. 
    */ // comment delimiter style pointers, anyone? 

// I'm surmising that 
void myfunk(void); 
    /* declares myfunk identically as the declaration 
       (prototype) of myfunc above. */ 

// It's silly code, but what about 
void myfunny(void, void, void) 
    /* takes three nothings-at-all passed in. If I 
       were the compiler I'd at least kick out a 
       warning about smart-asses. 
    */ 






On Sun, 2012-02-05 at 23:04 -0600, Kelly Martin wrote:
> On Sun, Feb 5, 2012 at 10:48 PM, techno curmudgeon <
> technocurmudgeon at gmail.com> wrote:
> 
> > In looking around (extracurricular reading?  I never even did that in
> > university!) a lot of the 'hello world' examples start with 'void' in
> > front of main().
> >
> > Researching "void" almost always says words to the effect "is the type
> > for a function does not return a value"...OK, got that.
> >
> > Then they launch into wildly gobbledegooky jargon about other uses.
> > Including "A C prototype taking no arguments, e.g. void f() above, has
> > been deprecated however in C99" (from a footnote in
> > http://en.wikipedia.org/wiki/Void_type).
> >
> > I don't want to get too off track here.  Since hello world worked, a
> > void keyword is not required (right?).  And since it didn't generate a
> > warning, it's not even bad form not to have one, right?
> >
> > I guess that's my question.  While not needed, is it good practice to
> > use the 'void' keyword?
> >
> > Thanks!
> > _______________________________________________
> > Courses mailing list
> > Courses at linuxchix.org
> > http://mailman.linuxchix.org/mailman/listinfo/courses
> >
> 
> I'm sure someone will correct me if I'm wrong, but what I recall being
> deprecated is not the use of void as the return type, but the use of an
> empty argument list (that is, the "()" in "void f()") in function
> prototypes.
> 
> Technically, what an empty argument list means is "arguments are
> unspecified", and the resulting function prototype yields a function which
> may permissibly be called with any number of arguments.  The C99 standard
> specifies that a function that takes no arguments shall be prototyped as
> "<returntype> f(void)", where the "(void)" indicates that the function
> explicitly takes no arguments.  Calling a function with an explicitly void
> formal argument list with any number of actual arguments other than zero is
> an compile-time error.  Calling a function prototyped with an unspecified
> formal argument list (or with no prototype at all) with any number of
> arguments other than zero generates, at most, a warning.
> 
> This has nothing to do with specifying a return type of void, which one
> should always declare for functions that do not have a return value.
> 
> Kelly
> _______________________________________________
> Courses mailing list
> Courses at linuxchix.org
> http://mailman.linuxchix.org/mailman/listinfo/courses