1 /*-
2 * Copyright (c) 1980 The Regents of the University of California.
3 * All rights reserved.
4 *
5 * %sccs.include.proprietary.c%
6 */
7
8 #ifndef lint
9 static char sccsid[] = "@(#)signal_.c 5.4 (Berkeley) 04/12/91";
10 #endif /* not lint */
11
12 /*
13 * change the action for a specified signal
14 *
15 * calling sequence:
16 * integer cursig, signal, savsig
17 * external proc
18 * cursig = signal(signum, proc, flag)
19 * where:
20 * 'cursig' will receive the current value of signal(2)
21 * 'signum' must be in the range 0 <= signum <= 32
22 *
23 * If 'flag' is negative, 'proc' must be an external proceedure name.
24 *
25 * If 'flag' is 0 or positive, it will be passed to signal(2) as the
26 * signal action flag. 0 resets the default action; 1 sets 'ignore'.
27 * 'flag' may be the value returned from a previous call to signal.
28 *
29 * This routine arranges to trap user specified signals so that it can
30 * pass the signum fortran style - by address. (boo)
31 */
32
33 #include "../libI77/f_errno.h"
34
35 static int (*dispatch[33])();
36 int (*signal())();
37 int sig_trap();
38
signal_(sigp,procp,flag)39 long signal_(sigp, procp, flag)
40 long *sigp, *flag;
41 int (*procp)();
42 {
43 int (*oldsig)();
44 int (*oldispatch)();
45
46 oldispatch = dispatch[*sigp];
47
48 if (*sigp < 0 || *sigp > 32)
49 return(-((long)(errno=F_ERARG)));
50
51 if (*flag < 0) /* function address passed */
52 {
53 dispatch[*sigp] = procp;
54 oldsig = signal((int)*sigp, sig_trap);
55 }
56
57 else /* integer value passed */
58 oldsig = signal((int)*sigp, (int)*flag);
59
60 if (oldsig == sig_trap)
61 return((long)oldispatch);
62 return((long)oldsig);
63 }
64
sig_trap(sn)65 sig_trap(sn)
66 int sn;
67 {
68 long lsn = (long)sn;
69 return((*dispatch[sn])(&lsn));
70 }
71