.rdata section in Cygwin executables?

[Egor Duda]

Joe Buehler wrote:
> The emacs recompile fails because there is a section in
> the initially built emacs.exe named ".rdata" that the
> unexec() code for Cygwin is not expecting.  The section
> appears to have something to do with exception handling
> and is only 1k in size.

.rdata is a section where read-only data, such as constants, is stored.
Most modern OSes and toolchain try to put as much info as possible to
read-only segments of binary image because it reduce memory required by
programs to run (when program is fork()ed, for instance, read-only pages 
may be shared between processes)

On linux such section is called .rodata, so probably you can take a look 
how linux version of emacs deals with that.

> I'm reading up on this at the moment, but a couple
> questions occur to me that someone here might be able
> to answer off the top of their head:
> 
> - can .rdata just be combined with the preceeding .data
>   section?

It's possible, but it's not the Right Way (tm).

> - perhaps there is a way to do this with the linker so
>   I don't have to change the emacs unexec() code?

You may write your own linker script so that all rdata section will be 
put to .data when emacs.exe is linked, but again, it doesn't look as the 
proper way to deal with the problem.

egor.