Mail Archives: djgpp/1999/02/01/01:06:36
I have several questions regarding signals. A search of the faq, info
files, website, and archive only partially answered these.
1. DJGPP 2.02 masks FPU exceptions by default but earlier DJGPPs do
not.
-- Is there a #define that will distinguish DJGPP 2.02 and later
versions from earlier versions? Not critically important.
-- In pre-2.02, FPU exceptions are masked using _control87.
The info files show _control87 accepting two unsigned ints, one
called a 'new control word' the other a 'mask'. It isn't
made clear, however, how the _control87 combines these with the
FPU state. Like, does it OR with the 'new control word' and
AND with the 'mask' or what, precisely? The mailing list
archives did not answer this. This IS important!
-- Do other Intel arch GCC development environments (Cygnus,
etc.) behave consistently about the FPU? Do all support
a _control87 in float.h with the exact same syntax and
semantics?
-- Non-GCC DOS and Windows compilers -- How do these manage
FPU exceptions?
-- How are FPU exceptions managed under Linux using GCC, or
using other compilers?
-- How do other CPU architectures manage FPU exceptions?
2. The signal handling mechanism for setting signal handlers and
the like is uniform among POSIX-compliant development
environments right?
3. Is there a standard C/C++ library function to launch an external
app synchronously regardless of whether the OS has multitasking
support?
4. Is there a way to launch a child program and capture stderr
from it, but not stdout? (I assume yes since the DJ util redir
must do it.) Is there such a method that is uniform across
many operating systems?
5. What happens to a DJGPP app if it launches a child that catches
a fatal signal, e.g. SIGSEGV? Is there a way to ensure that
the launching app stays stable and perceives it as the child
returning errorlevel 255? How does this translate to Linux
and other protected mode environments?
--
.*. "Clouds are not spheres, mountains are not cones, coastlines are not
-() < circles, and bark is not smooth, nor does lightning travel in a
`*' straight line." -------------------------------------------------
-- B. Mandelbrot |http://surf.to/pgd.net
_____________________ ____|________ Paul Derbyshire pderbysh AT usa DOT net
Programmer & Humanist|ICQ: 10423848|
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