Annotation of 43BSDTahoe/ucb/window/wwrint.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1983 Regents of the University of California.
        !             3:  * All rights reserved.
        !             4:  *
        !             5:  * Redistribution and use in source and binary forms are permitted
        !             6:  * provided that the above copyright notice and this paragraph are
        !             7:  * duplicated in all such forms and that any documentation,
        !             8:  * advertising materials, and other materials related to such
        !             9:  * distribution and use acknowledge that the software was developed
        !            10:  * by the University of California, Berkeley.  The name of the
        !            11:  * University may not be used to endorse or promote products derived
        !            12:  * from this software without specific prior written permission.
        !            13:  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
        !            14:  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
        !            15:  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
        !            16:  */
        !            17: 
        !            18: #ifndef lint
        !            19: static char sccsid[] = "@(#)wwrint.c   3.7 (Berkeley) 6/29/88";
        !            20: #endif /* not lint */
        !            21: 
        !            22: #include "ww.h"
        !            23: #include <fcntl.h>
        !            24: #include <sys/signal.h>
        !            25: 
        !            26: /*
        !            27:  * Tty input interrupt handler.
        !            28:  * (1) Read input into buffer (wwib*).
        !            29:  * (2) Set the interrupt flag if anything is read.
        !            30:  * Currently, the last is used to get out of the blocking
        !            31:  * select() in wwiomux().
        !            32:  * To avoid race conditions, we only modify wwibq in here, except
        !            33:  * when the buffer is empty; and everywhere else, we only change wwibp.
        !            34:  * It should be completely safe.
        !            35:  */
        !            36: wwrint()
        !            37: {
        !            38:        register n;
        !            39: 
        !            40:        if (wwibp == wwibq)
        !            41:                wwibp = wwibq = wwib;
        !            42:        wwnread++;
        !            43:        (void) fcntl(0, F_SETFL, FNDELAY|wwnewtty.ww_fflags);
        !            44:        n = read(0, wwibq, wwibe - wwibq);
        !            45:        (void) fcntl(0, F_SETFL, wwnewtty.ww_fflags);
        !            46:        if (n > 0) {
        !            47:                wwibq += n;
        !            48:                wwnreadc += n;
        !            49:                wwsetintr();
        !            50:        } else if (n == 0)
        !            51:                wwnreadz++;
        !            52:        else
        !            53:                wwnreade++;
        !            54: }

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