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This commit is contained in:
Jim Meyering 1994-08-19 13:13:48 +00:00
parent 1763c83a50
commit e50688802c
1 changed files with 51 additions and 13 deletions
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64
lib/ftruncate.c
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@ -1,10 +1,27 @@
/* ftruncate emulations that work on some System V's.
This file is in the public domain. */
This file is in the public domain. */
#ifdef HAVE_CONFIG_H
#if defined (CONFIG_BROKETS)
/* We use <config.h> instead of "config.h" so that a compilation
using -I. -I$srcdir will use ./config.h rather than $srcdir/config.h
(which it would do because it found this file in $srcdir). */
#include <config.h>
#else
#include "config.h"
#endif
#endif
#include <sys/types.h>
#include <fcntl.h>
#include <errno.h>
#ifndef STDC_HEADERS
extern int errno;
#endif
#ifdef F_CHSIZE
int
ftruncate (fd, length)
int fd;
@ -12,14 +29,17 @@ ftruncate (fd, length)
{
return fcntl (fd, F_CHSIZE, length);
}
#else
#else /* not F_CHSIZE */
#ifdef F_FREESP
/* The following function was written by
kucharsk@Solbourne.com (William Kucharski) */
/* By William Kucharski <kucharsk@netcom.com>. */
#include <sys/stat.h>
#include <errno.h>
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
int
ftruncate (fd, length)
@ -44,23 +64,28 @@ ftruncate (fd, length)
}
else
{
/* Truncate length. */
fl.l_whence = 0;
fl.l_len = 0;
fl.l_start = length;
fl.l_type = F_WRLCK; /* Write lock on file space. */
fl.l_type = F_WRLCK; /* write lock on file space */
/* This relies on the *undocumented* F_FREESP argument to fcntl,
which truncates the file so that it ends at the position
indicated by fl.l_start. Will minor miracles never cease? */
/* This relies on the UNDOCUMENTED F_FREESP argument to
fcntl, which truncates the file so that it ends at the
position indicated by fl.l_start.
Will minor miracles never cease? */
if (fcntl (fd, F_FREESP, &fl) < 0)
return -1;
}
return 0;
}
#else
#else /* not F_CHSIZE nor F_FREESP */
#ifdef HAVE_CHSIZE
int
ftruncate (fd, length)
int fd;
@ -68,5 +93,18 @@ ftruncate (fd, length)
{
return chsize (fd, length);
}
#endif
#endif
#else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */
int
ftruncate (fd, length)
int fd;
off_t length;
{
errno = EIO;
return -1;
}
#endif /* not HAVE_CHSIZE */
#endif /* not F_FREESP */
#endif /* not F_CHSIZE */