From:	"Tim" <t DOT j DOT _no_spam AT btinternet DOT com>
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: does kbhit() works outside <PC.H> ???
Date:	Sat, 15 Mar 2003 09:23:39 +0000 (UTC)
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Helen



The function kbhit() is not stored in pc.h header file, that is just where
its prototype is located. The function itself is in one of the djgpp
libraries which automatically gets linked into your project when you
compile.



A prototype is just used to tell the compiler what parameters are needed in
order to call to a function that is not part current source file*. If no
prototype is available the compiler will just assume that the function will
accept and return integers and build the code accordingly. If you set the
compiler directive -Wmissing-prototypes it would have warned you that you
had no prototype for the kbhit() function.



Headers also include macros and constants that are related to the various
functions the it represents. kbhit() is such a simple function that you were
able to use it with out any problems, but if you had tied to use something
like settime() without the header file you would have found that the
compiler would not be able to compile because it would not have any
information about the required data structure associated with that function.



I hope this helps a little,



* This is by no means a complete explanation and a read of a 'C' programming
guide should fill in the gaps.





Tim



"helen" <lab_darzo AT libero DOT it> wrote in message
news:ea10a10d62eaa7aea05133d2c5488823 DOT 113557 AT mygate DOT mailgate DOT org...
>
> I have DJGPP on win98 and win2k
>
> if I write the following:
>
> ----
> #include <stdio.h>
> /*  DO-WHILE */
> int main()
> {
> int x=0;
>
> do {
> x=x+1;
> printf("%5d",x);
> rest(100);
> } while (!kbhit());
>
> return 0;
> }
> ----
>
> I wouldn't expect it to work (isn't kbhit() defined in <pc.h> ?)
> but IT WORKS INSTEAD !
>
> also if I add
> #include <conio.h>
>
> it also works and I do not need to use
> _conio_kbhit()
>
> other functions defined in conio.h also work, even if I don't include
> the conio.h !!
> Like:
> clrscr(), or textcolor(); and also rest();
>
> how do you explain that ?
>
>
> helen (for once it works MORE than I need it to!!)
>
>
> --
> Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

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