70 lines
1.7 KiB
C
70 lines
1.7 KiB
C
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/* dup2.c
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The Unix dup2 function, for systems which only have dup.
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Copyright (C) 1985, 1986, 1987, 1988, 1990 Free Software Foundation, Inc.
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This file is part of the Taylor UUCP package.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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The author of the program may be contacted at ian@airs.com or
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c/o Infinity Development Systems, P.O. Box 520, Waltham, MA 02254.
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*/
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#include "uucp.h"
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#include "sysdep.h"
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#include <errno.h>
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#if HAVE_FCNTL_H
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#include <fcntl.h>
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#else
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#if HAVE_SYS_FILE_H
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#include <sys/file.h>
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#endif
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#endif
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/* I basically took this from the emacs 18.57 distribution, although I
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cleaned it up a bit and made it POSIX compliant. */
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int
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dup2 (oold, onew)
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int oold;
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int onew;
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{
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if (oold == onew)
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return onew;
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(void) close (onew);
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#ifdef F_DUPFD
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return fcntl (oold, F_DUPFD, onew);
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#else
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{
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int onext, oret, isave;
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onext = dup (oold);
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if (onext == onew)
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return onext;
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if (onext < 0)
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return -1;
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oret = dup2 (oold, onew);
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isave = errno;
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(void) close (onext);
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errno = isave;
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return oret;
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}
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#endif
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}
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