RE: jmp_buf size?

RE: jmp_buf size?

[Jay]

What is up with the size of jmp_buf?
It appears that setjmp.h confuses bytes and ints, specifically in the Cygwin case.
_JBLEN should be 13, not 13*4.
or #define _JBTYPE to char, but that doesn't work as easily.


?
 
 
I applied a local hack workaround, something like:
 
 
  typedef unsigned char JBTYPE __attribute(align(4));  
  #define _JBTYPE _JBTYPE 
  #include  
 
 
Though my larger goal, of implementing (deprecated-in-favor-of-pthreads) Posix get/make/set/swapcontext I gave up on anyway, at least via layering over setjmp/longjmp. They may be implementable via Win32 fibers, though the overall thing still perhaps dodgy and useless ("user more threads"...).
 
 
I realize that jmp_buf is something "deep" and system specific, not to be messed with lightly, but I'm also pretty darn certain that Cygwin declares its own jmp_buf incorrectly.
I also realize that larger than needed is safe, "just" wasteful, and possibly "future proof".
It still seems like a mistake.
 

 - Jay

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Re: jmp_buf size?

[Larry Hall (Cygwin)]

Jay wrote:
> What is up with the size of jmp_buf?
> It appears that setjmp.h confuses bytes and ints, specifically in the Cygwin case.
> _JBLEN should be 13, not 13*4.
> or #define _JBTYPE to char, but that doesn't work as easily.

<snip>

Did you see this reply to your first inquiry on this subject?

<http://cygwin.com/ml/cygwin/2009-01/msg00863.html>

-- 
Larry Hall                              http://www.rfk.com
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
216 Dalton Rd.                          (508) 893-9889 - FAX
Holliston, MA 01746

_____________________________________________________________________

A: Yes.
 > Q: Are you sure?
 >> A: Because it reverses the logical flow of conversation.
 >>> Q: Why is top posting annoying in email?

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RE: jmp_buf size?

[Jay]

Thanks, sorry, I didn't see that.
 
 
 - Jay


----------------------------------------
> Date: Wed, 4 Feb 2009 18:49:50 -0500
> From: reply-to-list-only-lh@cygwin.com
> To: cygwin@cygwin.com
> CC: jay.krell@cornell.edu
> Subject: Re: jmp_buf size?
>
> Jay wrote:
>> What is up with the size of jmp_buf?
>> It appears that setjmp.h confuses bytes and ints, specifically in the Cygwin case.
>> _JBLEN should be 13, not 13*4.
>> or #define _JBTYPE to char, but that doesn't work as easily.
>
> 
>
> Did you see this reply to your first inquiry on this subject?
>
> 
>
> --
> Larry Hall http://www.rfk.com

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Re: jmp_buf size?

[Christopher Faylor]

On Thu, Jan 29, 2009 at 05:07:42PM +0000, Jay wrote:
>
>What is up with the size of jmp_buf?
>It appears that setjmp.h confuses bytes and ints.
>_JBLEN should be 13, not 13*4.
>or #define _JBTYPE to char, but that doesn't work as easily.

Huh.  You would think that the fact that Cygwin's definition of _JBLEN
differed from every other definition would have been a clue that
something was amiss here.

It appears to be an ancient (pre-2000 when I pulled newlib onto
sourceware.org) typo but there is no easy way we can change this now.

cgf

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jmp_buf size?

[Jay]

What is up with the size of jmp_buf?
It appears that setjmp.h confuses bytes and ints.
_JBLEN should be 13, not 13*4.
or #define _JBTYPE to char, but that doesn't work as easily.
 
?
 
 - Jay

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