4.3BSD - /usr/src/usr.lib/libF77/signal_.c

   1: /*
   2:  * Copyright (c) 1980 Regents of the University of California.
   3:  * All rights reserved.  The Berkeley software License Agreement
   4:  * specifies the terms and conditions for redistribution.
   5:  *
   6:  *	@(#)signal_.c	5.3	9/11/85
   7:  *
   8:  * change the action for a specified signal
   9:  *
  10:  * calling sequence:
  11:  *	integer cursig, signal, savsig
  12:  *	external proc
  13:  *	cursig = signal(signum, proc, flag)
  14:  * where:
  15:  *	'cursig' will receive the current value of signal(2)
  16:  *	'signum' must be in the range 0 <= signum <= 32
  17:  *
  18:  *	If 'flag' is negative, 'proc' must be an external proceedure name.
  19:  *
  20:  *	If 'flag' is 0 or positive, it will be passed to signal(2) as the
  21:  *	signal action flag. 0 resets the default action; 1 sets 'ignore'.
  22:  *	'flag' may be the value returned from a previous call to signal.
  23:  *
  24:  * This routine arranges to trap user specified signals so that it can
  25:  * pass the signum fortran style - by address. (boo)
  26:  */
  27: 
  28: #include    "../libI77/f_errno.h"
  29: 
  30: static int (*dispatch[33])();
  31: int (*signal())();
  32: int sig_trap();
  33: 
  34: long signal_(sigp, procp, flag)
  35: long *sigp, *flag;
  36: int (*procp)();
  37: {
  38:     int (*oldsig)();
  39:     int (*oldispatch)();
  40: 
  41:     oldispatch = dispatch[*sigp];
  42: 
  43:     if (*sigp < 0 || *sigp > 32)
  44:         return(-((long)(errno=F_ERARG)));
  45: 
  46:     if (*flag < 0)  /* function address passed */
  47:     {
  48:         dispatch[*sigp] = procp;
  49:         oldsig = signal((int)*sigp, sig_trap);
  50:     }
  51: 
  52:     else        /* integer value passed */
  53:         oldsig = signal((int)*sigp, (int)*flag);
  54: 
  55:     if (oldsig == sig_trap)
  56:         return((long)oldispatch);
  57:     return((long)oldsig);
  58: }
  59: 
  60: sig_trap(sn)
  61: int sn;
  62: {
  63:     long lsn = (long)sn;
  64:     return((*dispatch[sn])(&lsn));
  65: }

Defined functions