At 04:32 AM 2/4/2010, you wrote:
>While getting to grips with C18 quite happily, I discovered
>(http://users.aber.ac.uk/auj/voidmain.shtml) that using "void main
>(void)" , as most C18 demo code does, is frowned upon.
>
>I'm asking any seasoned C18 philosophers out there; is this cause for
>concern? I don't know enough about C yet to predict whether this is
>really an issue or not, purely in the case of using C18 for PIC development.
>
>Regards,
>Matt

IMHO, this is a case of a bit of knowledge being dangerous, or at least
annoying.

If you read the C standard ISO/IEC 9899:1999 (E) , it is only a requirement of
conforming *hosted* implementations that main be defined as int. Parameters
are optional.

Typically PICs operate in a *freestanding* environment (no operating system),
which means that there is no precise requirement as to the effect of program
termination, what code is actually called at start-up-- it's "implementation
defined".

In either hosted or freestanding conforming implementations, initialization
of statics is guaranteed, though.

So, I don't think it's a big deal one way or the other. If you define main
as int you have to return something (typically 0 for successful termination)
or the compiler will complain, so it might end up using a few more bytes.
In freestanding implementations, of course, your program should *never*
terminate, because there is nowhere to go. Maybe there's an implementation
defined reset or something like that.

Usually if you're using C, a few more bytes get lost in the noise. Personally,
I use void main(void) and look at the assy code of a very small program to
make sure I know precisely what is going on with the program and startup
code. It's a bit irritating, because often there is an unnecessary call, which
uses a stack level.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com


-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist