62 lines
2.0 KiB
C
62 lines
2.0 KiB
C
/* Copyright (C) 1991 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library 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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The GNU C Library is distributed in the hope that it will be useful,
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but 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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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/* Initialize STREAM as necessary.
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This may change I/O functions, give a buffer, etc.
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If no buffer is allocated, but the bufsize is set,
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the bufsize will be used to allocate the buffer. */
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void
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DEFUN(__stdio_init_stream, (stream), FILE *stream)
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{
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register CONST int fd = *(int *) stream->__cookie;
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struct stat statb;
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if (stream->__buffer != NULL || stream->__userbuf)
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/* If's unbuffered by request, we can't do anything useful. */
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return;
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/* Find out what sort of file this is. */
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if (__fstat(fd, &statb) < 0)
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return;
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if (S_ISFIFO(statb.st_mode))
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{
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/* It's a named pipe (FIFO). Make it unbuffered. */
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stream->__userbuf = 1;
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return;
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}
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if (S_ISCHR(statb.st_mode))
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{
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/* It's a character device.
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Make it line-buffered if it's a terminal. */
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if (__isatty(fd))
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stream->__linebuf = 1;
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}
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/* Use the block-size field to determine
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the system's optimal buffering size. */
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stream->__bufsize = statb.st_blksize;
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}
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