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From: jbs30000 AT aol DOT com (Joel)
Newsgroups: comp.os.msdos.djgpp
Subject: Re: Ignore my last post, please read this
Date: 30 Sep 2003 20:42:10 -0700
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Eli Zaretskii <eliz AT elta DOT co DOT il> wrote in message news:<ur81yerzg DOT fsf AT elta DOT co DOT il>...
> > From: jbs30000 AT aol DOT com (Joel)
> > Newsgroups: comp.os.msdos.djgpp
> > Date: 29 Sep 2003 17:37:26 -0700
> > 
> > OK, after looking at my last post, I see it's too long and hard to
> > read, so I'll make this question very simple.  If a routine includes
> > these external declarations:
> > 
> > extern void Bank_Plot_8(unsigned short X, unsigned short Y, unsigned
> > char R, unsigned char G, unsigned char B, unsigned char LO);
> > 
> > extern void Linear_Plot_8(unsigned short X, unsigned short Y, unsigned
> > char R, unsigned char G, unsigned char B, unsigned char LO);
> > 
> > extern void (*Plot_Pixel)(unsigned short X, unsigned short Y, unsigned
> > char R, unsigned char G, unsigned char B, unsigned char LO);
> > 
> > extern unsigned long (*Pixel_Point)(unsigned short X, unsigned short
> > Y);
> > 
> > And then I go
> > 
> > Plot_Pixel = &Linear_Plot_8;
> > 
> > Pixel_Point = &Linear_Point_8;
> > 
> > And I get an error:
> > 
> > Error: undefined reference to `Linear_Point_8(unsigned short, unsigned
> > short)
> > 
> > What could be the problem?  Thank you.
> 
> The linker needs to see the _definition_ of that function, not just
> its prototype declaration.  That is, when you link your program, one
> of the object files you link must have the code of Linear_Point_8.

Thank you.  Funny thing is, I thought that I did have the code
written.  But, at any rate, I have it written now.  Thanks again.