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Annotation of 42BSD/usr.lib/libU77/signal_.c, revision 1.1

1.1     ! root        1: /*
        !             2: char id_signal[] = "@(#)signal_.c      1.4";
        !             3:  *
        !             4:  * change the action for a specified signal
        !             5:  *
        !             6:  * calling sequence:
        !             7:  *     integer cursig, signal, savsig
        !             8:  *     external proc
        !             9:  *     cursig = signal(signum, proc, flag)
        !            10:  * where:
        !            11:  *     'cursig' will receive the current value of signal(2)
        !            12:  *     'signum' must be in the range 0 <= signum <= 16
        !            13:  *
        !            14:  *     If 'flag' is negative, 'proc' must be an external proceedure name.
        !            15:  *     
        !            16:  *     If 'flag' is 0 or positive, it will be passed to signal(2) as the
        !            17:  *     signal action flag. 0 resets the default action; 1 sets 'ignore'.
        !            18:  *     'flag' may be the value returned from a previous call to signal.
        !            19:  *
        !            20:  * This routine arranges to trap user specified signals so that it can
        !            21:  * pass the signum fortran style - by address. (boo)
        !            22:  */
        !            23: 
        !            24: #include       "../libI77/f_errno.h"
        !            25: 
        !            26: static int (*dispatch[17])();
        !            27: int (*signal())();
        !            28: int sig_trap();
        !            29: 
        !            30: long signal_(sigp, procp, flag)
        !            31: long *sigp, *flag;
        !            32: int (*procp)();
        !            33: {
        !            34:        int (*oldsig)();
        !            35:        int (*oldispatch)();
        !            36: 
        !            37:        oldispatch = dispatch[*sigp];
        !            38: 
        !            39:        if (*sigp < 0 || *sigp > 16)
        !            40:                return(-((long)(errno=F_ERARG)));
        !            41: 
        !            42:        if (*flag < 0)  /* function address passed */
        !            43:        {
        !            44:                dispatch[*sigp] = procp;
        !            45:                oldsig = signal((int)*sigp, sig_trap);
        !            46:        }
        !            47: 
        !            48:        else            /* integer value passed */
        !            49:                oldsig = signal((int)*sigp, (int)*flag);
        !            50: 
        !            51:        if (oldsig == sig_trap)
        !            52:                return((long)oldispatch);
        !            53:        return((long)oldsig);
        !            54: }
        !            55: 
        !            56: sig_trap(sn)
        !            57: int sn;
        !            58: {
        !            59:        long lsn = (long)sn;
        !            60:        return((*dispatch[sn])(&lsn));
        !            61: }

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