/* ftruncate emulations that work on some System V's.
- This file is in the public domain. */
+ This file is in the public domain. */
+
+#include <config.h>
+
+/* Specification. */
+#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#ifdef F_CHSIZE
+
int
-ftruncate (fd, length)
- int fd;
- off_t length;
+ftruncate (int fd, off_t length)
{
return fcntl (fd, F_CHSIZE, length);
}
-#else
-#ifdef F_FREESP
-/* The following function was written by
- kucharsk@Solbourne.com (William Kucharski) */
-#include <sys/stat.h>
-#include <errno.h>
-#include <unistd.h>
+#else /* not F_CHSIZE */
+# ifdef F_FREESP
+
+/* By William Kucharski <kucharsk@netcom.com>. */
+
+# include <sys/stat.h>
+# include <errno.h>
int
-ftruncate (fd, length)
- int fd;
- off_t length;
+ftruncate (int fd, off_t length)
{
struct flock fl;
struct stat filebuf;
}
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 */
+# if HAVE_CHSIZE /* native Windows, e.g. mingw */
+
int
-ftruncate (fd, length)
- int fd;
- off_t length;
+ftruncate (int fd, off_t length)
{
return chsize (fd, length);
}
-#endif
-#endif
+
+# else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */
+
+# include <errno.h>
+
+int
+ftruncate (int fd, off_t length)
+{
+ errno = EIO;
+ return -1;
+}
+
+# endif /* not HAVE_CHSIZE */
+# endif /* not F_FREESP */
+#endif /* not F_CHSIZE */