1 /* Convenience declarations when working with <signal.h>. 2 3 Copyright (C) 2008-2011 Free Software Foundation, Inc. 4 5 This program is free software: you can redistribute it and/or modify 6 it under the terms of the GNU General Public License as published by 7 the Free Software Foundation; either version 3 of the License, or 8 (at your option) any later version. 9 10 This program is distributed in the hope that it will be useful, 11 but WITHOUT ANY WARRANTY; without even the implied warranty of 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 GNU General Public License for more details. 14 15 You should have received a copy of the GNU General Public License 16 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 17 18 #ifndef _GL_SIG_HANDLER_H 19 #define _GL_SIG_HANDLER_H 20 21 #include <signal.h> 22 23 /* Convenience type when working with signal handlers. */ 24 typedef void (*sa_handler_t) (int); 25 26 /* Return the handler of a signal, as a sa_handler_t value regardless 27 of its true type. The resulting function can be compared to 28 special values like SIG_IGN but it is not portable to call it. */ 29 static inline sa_handler_t 30 get_handler (struct sigaction const *a) 31 { 32 #ifdef SA_SIGINFO 33 /* POSIX says that special values like SIG_IGN can only occur when 34 action.sa_flags does not contain SA_SIGINFO. But in Linux 2.4, 35 for example, sa_sigaction and sa_handler are aliases and a signal 36 is ignored if sa_sigaction (after casting) equals SIG_IGN. So 37 use (and cast) sa_sigaction in that case. */ 38 if (a->sa_flags & SA_SIGINFO) 39 return (sa_handler_t) a->sa_sigaction; 40 #endif 41 return a->sa_handler; 42 } 43 44 #endif /* _GL_SIG_HANDLER_H */ 45