Am 21.11.2010, 19:47 Uhr, schrieb Peter Federighi <[email protected]>:
I'd still like to know if there's a better way/native way to trap C
style signals
in D. Or is there a D way of programming a timer and finding terminal
window size
changes?
I don't think there are any D libraries to handle posix signals. Posix
signals are a pita. In theory all functions you call in posix signal
handlers must be signal safe and the requirements for that are very
strict. Allocating memory in a signal handler is not safe for example. In
practice, Linux for example is way more tolerant that the posix
specification, so you often won't experience any problems with faulty
signal handlers. Problems start to appear when you port to different OS
which might be less forgiving. And as you're relying on unspecified
features, a future update in kernel / external libraries could break your
application.
(http://en.wikipedia.org/wiki/Signal_(computing)#Risks)
Because of these issues many people try to avoid signals whenever
possible. If signals are needed the recommendation often is to use
synchronous signal handling where all those issues don't exist. The key to
synchronous signal handling is the sigwait
function(http://linux.die.net/man/3/sigwait) but it blocks one thread all
the time.
Other possible solutions: signals can be managed with libev. I guess it
uses synchronous signal handling internally, but it allows you to wait for
an io event, signal, and other things in one thread. libev also has timers.
I've also seen an timer implementation which uses a mutex and condition
variables with timeouts to simulate a timer. Works without signals or any
special system support, but I don't know of an implementation for D.
The simplest(and least effective) possibility is to use a loop,
Thread.sleep() and polling
//Pseudo code, functions might have other names ;-)
Size lastSize;
while(true)
{
auto size = getWindowSize();
if(size != lastSize)
...
Thread.sleep(1000);
}
--
Johannes Pfau
