Re: How do I do generic programming in C?

Hi

On May 13, 6:21 pm, "Robbie Hatley"
<see.my.signat...@[EMAIL PROTECTED]
> wrote:
> If this was C++, I'd make the expand/extract function a template:
> So... is there any way of emulating templates in C?
> Or do I just have to live with duplicate functions?

AFAIK the nearest that you can get in C alone is a preprocessor macro,
using typenames as parameters.

This looks like:

#define COPY_MEMBERS(struct_type1,struct_type2) \
  ((struct_type1*)out)-> member_a= ((struct_type2*)out)-> member_a; \
  ((struct_type1*)out)-> member_b= ((struct_type2*)out)-> member_b; \
  ((struct_type1*)out)-> member_c= ((struct_type2*)out)-> member_c;


int ExpandSetupFrom1400 (setup1400_t const *in, setup_t *out){
  COPY_MEMBERS(setup_t,setup1400_t)
}

int ExtractSetupTo1400 (setup_t const *in, setup1400_t *out){
  COPY_MEMBERS(setup1400_t,setup_t)
}

This isn't significantly different from your idea of using #include,
but at least it is a bit easier to read, and doesn't risk confusing
make (etc) when you update the included file.

I use this method very regularly in developing image processing
operations that work on all types, eg:

http://vips.svn.sourceforge.net/viewvc/vips/vips7/trunk/libsrc/arithmetic/im_abs.c?revision=233&view=markup