Tomas Hajny wrote:
On Wed, January 1, 2014 20:48, Mark Morgan Lloyd wrote:
When reading characters from a program's stdin using fpRead(), what's
the best way of suppressing ^C so that it doesn't raise SIGTERM or
whatever? I want to be able to handle signals indicating e.g. a UPS
power-failure message, but not to get trivial stuff from the keyboard.
Platform is predominantly Linux, possibly also Solaris and one of the
BSDs. Anybody porting the program to Windows will have to do their own
dirty work :-)
The general platform independent solution would have been 'Crt.CheckBreak
:= false' (or System.SysSetCtrlBreakHandler without unit Crt should you
not use/need that) - except for the fact that maintainers of most
platforms (all those mentioned by you) decided not to implement/support
this functionality and thus it would not work for those platforms you are
interested in... :-/
Good point. In practice using Crt might be a problem when I come to
adding an alternative graphical frontend to the emulator: I think this
highlights (as has been discussed elsewhere) the lack of a simple
terminal component in Lazarus.
I've played around a bit and find that in Linux (other platforms
untested) provided that I add action.Sa_Flags := SA_SIGINFO; I can get
the PID inside the signal handler. This is zero for a ^C, which
potentially allows one to distinguish between a spurious ^C and a SIGINT
sent by kill.
--
Mark Morgan Lloyd
markMLl .AT. telemetry.co .DOT. uk
[Opinions above are the author's, not those of his employers or colleagues]
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