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[glibc.git] / sysdeps / generic / allocrtsig.c
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1 /* Handle real-time signal allocation.
2 Copyright (C) 1997,98,99,2002 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
21 #include <signal.h>
23 /* In these variables we keep track of the used variables. If the
24 platform does not support any real-time signals we will define the
25 values to some unreasonable value which will signal failing of all
26 the functions below. */
27 #ifndef __SIGRTMIN
28 static int current_rtmin = -1;
29 static int current_rtmax = -1;
30 #else
31 static int current_rtmin;
32 static int current_rtmax;
34 static int initialized;
36 #include "testrtsig.h"
38 static void
39 init (void)
41 if (!kernel_has_rtsig ())
43 current_rtmin = -1;
44 current_rtmax = -1;
46 else
48 current_rtmin = __SIGRTMIN;
49 current_rtmax = __SIGRTMAX;
51 initialized = 1;
53 #endif
55 /* Return number of available real-time signal with highest priority. */
56 int
57 __libc_current_sigrtmin (void)
59 #ifdef __SIGRTMIN
60 if (!initialized)
61 init ();
62 #endif
63 return current_rtmin;
66 /* Return number of available real-time signal with lowest priority. */
67 int
68 __libc_current_sigrtmax (void)
70 #ifdef __SIGRTMIN
71 if (!initialized)
72 init ();
73 #endif
74 return current_rtmax;
77 /* Allocate real-time signal with highest/lowest available
78 priority. Please note that we don't use a lock since we assume
79 this function to be called at program start. */
80 int
81 __libc_allocate_rtsig (int high)
83 #ifndef __SIGRTMIN
84 return -1;
85 #else
86 if (!initialized)
87 init ();
88 if (current_rtmin == -1 || current_rtmin > current_rtmax)
89 /* We don't have anymore signal available. */
90 return -1;
92 return high ? current_rtmin++ : current_rtmax--;
93 #endif