Re: [TCLCORE] SEH handling: why not use excpt.h on mingw?

[Kevin K. <kev...@gm...>]

Anton Kovalenko wrote:
> Hello Tcl developers.
> 
> On Windows platform, Tcl has to catch "structured exceptions" at some
> places.  It is implemented using the microsoft's C language extension
> (for MSVC) or a bunch of x86 assembly code (for mingw).

As far as I've been able to determine, the SEH code is simply
not an issue for Win64. It appears in exactly four places in
Tcl:

tclWin32Dll.c - It wraps around the CPUID instruction, which
faulted on 80386, 80486 and 80486SX (80486DX supported it).
None of these ancient machines supported 64-bit operation.
(Moreover, the features we're looking for aren't relevant
on 64-bit machines so we don't even look.)

tclWinChan.c - This is weird code that protects against a process
crash if an invalid handle is presented to Tcl_MakeFileChannel.
I'd contend that the correct action in that case is to crash.

tclWinFCmd.c (2 places) - Windows NT 3.51 and Windows NT 4.0
(but not anything newer) would get a pointer smash deep inside the
system libraries if [file rename] or [file copy] was called
on a serial port. Win2k, WinXP, and everything newer correctly
return an error status.  So, not an issue for 64-bitters.

Others have tried to contribute 64-bit SEH code in the past,
and we've not put it in simply because it isn't needed.

-- 
73 de ke9tv/2, Kevin