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52 lines
1.9 KiB
C++
52 lines
1.9 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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signal/signal.cpp
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Configure and retrieve a signal handler.
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*******************************************************************************/
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#include <signal.h>
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#include <string.h>
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extern "C" void (*signal(int signum, void (*handler)(int)))(int)
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{
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// Create a structure describing the new handler.
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struct sigaction newact;
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memset(&newact, 0, sizeof(newact));
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sigemptyset(&newact.sa_mask);
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newact.sa_handler = handler;
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newact.sa_flags = SA_RESTART;
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// Register the new handler and atomically get the old.
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struct sigaction oldact;
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if ( sigaction(signum, &newact, &oldact) != 0 )
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return SIG_ERR;
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// We can't return the old handler properly if it's SA_SIGINFO or SA_COOKIE,
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// unless it's the common SIG_IGN or SIG_DFL handlers. Let's just say to the
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// caller that it's SIG_DFL and assume that they'll be using sigaction
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// instead if they wish to restore an old handler.
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if ( (oldact.sa_flags & (SA_SIGINFO | SA_COOKIE)) &&
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oldact.sa_handler != SIG_IGN &&
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oldact.sa_handler != SIG_DFL )
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return SIG_DFL;
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return oldact.sa_handler;
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}
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