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From: edward@runxtsa.runx.oz.au (Edward Birch)
Newsgroups: comp.lang.c++
Subject: C, C++ interrupt routines (UNIX)
Keywords: C,C++,signal
Message-ID: <1972@runxtsa.runx.oz.au>
Date: 14 Jul 90 15:06:37 GMT
Organization: RUNX Unix Timeshare.  Sydney, Australia.
Lines: 40


I am interested in some comments; am I correct with my analysis relating to
the below code, that the line `` cout << val << "\n"; '' is *very* dangerous.

	#include	<signal.h>
	#include	<stream.h>

	void
	func(int val)
	{
		// printf("%d\n", val);	// C   sample code

		cout << val << "\n";	// C++ sample code ...

					// I believe this to be invalid because
					// libC.a, etc is not re-entrant
					//   in particular malloc() and ::new()
	}

	main()
	{
		signal(SIGINT,  (PF)func);
		signal(SIGQUIT, (PF)func);

		// ...
	}

As I understand with C++ and for that matter C the above example is
to be *avoided* because the stdio or streams library can for example
invoke routines that are not re-entrant and those routines may for
example be executing when the interrupt in question is accepted (processed).
I refer in particular to malloc() which is used by default by
::new() for example.

Edward Birch

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