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From: Jay <jay DOT krell AT cornell DOT edu>
To: cygwin <cygwin AT cygwin DOT com>
Subject: RE: jmp_buf size?
Date: Wed, 4 Feb 2009 23:00:00 +0000
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What is up with the size of jmp_buf?
It appears that setjmp.h confuses bytes and ints, specifically in the Cygwi=
n case.
_JBLEN should be 13, not 13*4.
or #define _JBTYPE to char, but that doesn't work as easily.


?
=20
=20
I applied a local hack workaround, something like:
=20
=20
  typedef unsigned char JBTYPE __attribute(align(4));=20=20
  #define _JBTYPE _JBTYPE=20
  #include=20=20
=20
=20
Though my larger goal, of implementing (deprecated-in-favor-of-pthreads) Po=
six get/make/set/swapcontext I gave up on anyway, at least via layering ove=
r setjmp/longjmp. They may be implementable via Win32 fibers, though the ov=
erall thing still perhaps dodgy and useless ("user more threads"...).
=20
=20
I realize that jmp_buf is something "deep" and system specific, not to be m=
essed with lightly, but I'm also pretty darn certain that Cygwin declares i=
ts own jmp_buf incorrectly.
I also realize that larger than needed is safe, "just" wasteful, and possib=
ly "future proof".
It still seems like a mistake.
=20

 - Jay

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