patch 8.1.2094: the fileio.c file is too bigv8.1.2094

Problem:    The fileio.c file is too big.
Solution:   Move buf_write() to bufwrite.c. (Yegappan Lakshmanan,
            closes #4990)

1 files changed, 2559 insertions, 0 deletions

diff --git a/src/bufwrite.c b/src/bufwrite.c
new file mode 100644
index 000000000..13091a336
--- /dev/null
+++ b/src/bufwrite.c
@@ -0,0 +1,2559 @@
+/* vi:set ts=8 sts=4 sw=4 noet:
+ *
+ * VIM - Vi IMproved	by Bram Moolenaar
+ *
+ * Do ":help uganda"  in Vim to read copying and usage conditions.
+ * Do ":help credits" in Vim to see a list of people who contributed.
+ * See README.txt for an overview of the Vim source code.
+ */
+
+/*
+ * bufwrite.c: functions for writing a buffer
+ */
+
+#include "vim.h"
+
+#if defined(HAVE_UTIME) && defined(HAVE_UTIME_H)
+# include <utime.h>		// for struct utimbuf
+#endif
+
+#define SMALLBUFSIZE	256	// size of emergency write buffer
+
+/*
+ * Structure to pass arguments from buf_write() to buf_write_bytes().
+ */
+struct bw_info
+{
+    int		bw_fd;		// file descriptor
+    char_u	*bw_buf;	// buffer with data to be written
+    int		bw_len;		// length of data
+    int		bw_flags;	// FIO_ flags
+#ifdef FEAT_CRYPT
+    buf_T	*bw_buffer;	// buffer being written
+#endif
+    char_u	bw_rest[CONV_RESTLEN]; // not converted bytes
+    int		bw_restlen;	// nr of bytes in bw_rest[]
+    int		bw_first;	// first write call
+    char_u	*bw_conv_buf;	// buffer for writing converted chars
+    size_t	bw_conv_buflen; // size of bw_conv_buf
+    int		bw_conv_error;	// set for conversion error
+    linenr_T	bw_conv_error_lnum;  // first line with error or zero
+    linenr_T	bw_start_lnum;  // line number at start of buffer
+#ifdef USE_ICONV
+    iconv_t	bw_iconv_fd;	// descriptor for iconv() or -1
+#endif
+};
+
+/*
+ * Convert a Unicode character to bytes.
+ * Return TRUE for an error, FALSE when it's OK.
+ */
+    static int
+ucs2bytes(
+    unsigned	c,		// in: character
+    char_u	**pp,		// in/out: pointer to result
+    int		flags)		// FIO_ flags
+{
+    char_u	*p = *pp;
+    int		error = FALSE;
+    int		cc;
+
+
+    if (flags & FIO_UCS4)
+    {
+	if (flags & FIO_ENDIAN_L)
+	{
+	    *p++ = c;
+	    *p++ = (c >> 8);
+	    *p++ = (c >> 16);
+	    *p++ = (c >> 24);
+	}
+	else
+	{
+	    *p++ = (c >> 24);
+	    *p++ = (c >> 16);
+	    *p++ = (c >> 8);
+	    *p++ = c;
+	}
+    }
+    else if (flags & (FIO_UCS2 | FIO_UTF16))
+    {
+	if (c >= 0x10000)
+	{
+	    if (flags & FIO_UTF16)
+	    {
+		// Make two words, ten bits of the character in each.  First
+		// word is 0xd800 - 0xdbff, second one 0xdc00 - 0xdfff
+		c -= 0x10000;
+		if (c >= 0x100000)
+		    error = TRUE;
+		cc = ((c >> 10) & 0x3ff) + 0xd800;
+		if (flags & FIO_ENDIAN_L)
+		{
+		    *p++ = cc;
+		    *p++ = ((unsigned)cc >> 8);
+		}
+		else
+		{
+		    *p++ = ((unsigned)cc >> 8);
+		    *p++ = cc;
+		}
+		c = (c & 0x3ff) + 0xdc00;
+	    }
+	    else
+		error = TRUE;
+	}
+	if (flags & FIO_ENDIAN_L)
+	{
+	    *p++ = c;
+	    *p++ = (c >> 8);
+	}
+	else
+	{
+	    *p++ = (c >> 8);
+	    *p++ = c;
+	}
+    }
+    else    // Latin1
+    {
+	if (c >= 0x100)
+	{
+	    error = TRUE;
+	    *p++ = 0xBF;
+	}
+	else
+	    *p++ = c;
+    }
+
+    *pp = p;
+    return error;
+}
+
+/*
+ * Call write() to write a number of bytes to the file.
+ * Handles encryption and 'encoding' conversion.
+ *
+ * Return FAIL for failure, OK otherwise.
+ */
+    static int
+buf_write_bytes(struct bw_info *ip)
+{
+    int		wlen;
+    char_u	*buf = ip->bw_buf;	// data to write
+    int		len = ip->bw_len;	// length of data
+    int		flags = ip->bw_flags;	// extra flags
+
+    // Skip conversion when writing the crypt magic number or the BOM.
+    if (!(flags & FIO_NOCONVERT))
+    {
+	char_u		*p;
+	unsigned	c;
+	int		n;
+
+	if (flags & FIO_UTF8)
+	{
+	    // Convert latin1 in the buffer to UTF-8 in the file.
+	    p = ip->bw_conv_buf;	// translate to buffer
+	    for (wlen = 0; wlen < len; ++wlen)
+		p += utf_char2bytes(buf[wlen], p);
+	    buf = ip->bw_conv_buf;
+	    len = (int)(p - ip->bw_conv_buf);
+	}
+	else if (flags & (FIO_UCS4 | FIO_UTF16 | FIO_UCS2 | FIO_LATIN1))
+	{
+	    // Convert UTF-8 bytes in the buffer to UCS-2, UCS-4, UTF-16 or
+	    // Latin1 chars in the file.
+	    if (flags & FIO_LATIN1)
+		p = buf;	// translate in-place (can only get shorter)
+	    else
+		p = ip->bw_conv_buf;	// translate to buffer
+	    for (wlen = 0; wlen < len; wlen += n)
+	    {
+		if (wlen == 0 && ip->bw_restlen != 0)
+		{
+		    int		l;
+
+		    // Use remainder of previous call.  Append the start of
+		    // buf[] to get a full sequence.  Might still be too
+		    // short!
+		    l = CONV_RESTLEN - ip->bw_restlen;
+		    if (l > len)
+			l = len;
+		    mch_memmove(ip->bw_rest + ip->bw_restlen, buf, (size_t)l);
+		    n = utf_ptr2len_len(ip->bw_rest, ip->bw_restlen + l);
+		    if (n > ip->bw_restlen + len)
+		    {
+			// We have an incomplete byte sequence at the end to
+			// be written.  We can't convert it without the
+			// remaining bytes.  Keep them for the next call.
+			if (ip->bw_restlen + len > CONV_RESTLEN)
+			    return FAIL;
+			ip->bw_restlen += len;
+			break;
+		    }
+		    if (n > 1)
+			c = utf_ptr2char(ip->bw_rest);
+		    else
+			c = ip->bw_rest[0];
+		    if (n >= ip->bw_restlen)
+		    {
+			n -= ip->bw_restlen;
+			ip->bw_restlen = 0;
+		    }
+		    else
+		    {
+			ip->bw_restlen -= n;
+			mch_memmove(ip->bw_rest, ip->bw_rest + n,
+						      (size_t)ip->bw_restlen);
+			n = 0;
+		    }
+		}
+		else
+		{
+		    n = utf_ptr2len_len(buf + wlen, len - wlen);
+		    if (n > len - wlen)
+		    {
+			// We have an incomplete byte sequence at the end to
+			// be written.  We can't convert it without the
+			// remaining bytes.  Keep them for the next call.
+			if (len - wlen > CONV_RESTLEN)
+			    return FAIL;
+			ip->bw_restlen = len - wlen;
+			mch_memmove(ip->bw_rest, buf + wlen,
+						      (size_t)ip->bw_restlen);
+			break;
+		    }
+		    if (n > 1)
+			c = utf_ptr2char(buf + wlen);
+		    else
+			c = buf[wlen];
+		}
+
+		if (ucs2bytes(c, &p, flags) && !ip->bw_conv_error)
+		{
+		    ip->bw_conv_error = TRUE;
+		    ip->bw_conv_error_lnum = ip->bw_start_lnum;
+		}
+		if (c == NL)
+		    ++ip->bw_start_lnum;
+	    }
+	    if (flags & FIO_LATIN1)
+		len = (int)(p - buf);
+	    else
+	    {
+		buf = ip->bw_conv_buf;
+		len = (int)(p - ip->bw_conv_buf);
+	    }
+	}
+
+#ifdef MSWIN
+	else if (flags & FIO_CODEPAGE)
+	{
+	    // Convert UTF-8 or codepage to UCS-2 and then to MS-Windows
+	    // codepage.
+	    char_u	*from;
+	    size_t	fromlen;
+	    char_u	*to;
+	    int		u8c;
+	    BOOL	bad = FALSE;
+	    int		needed;
+
+	    if (ip->bw_restlen > 0)
+	    {
+		// Need to concatenate the remainder of the previous call and
+		// the bytes of the current call.  Use the end of the
+		// conversion buffer for this.
+		fromlen = len + ip->bw_restlen;
+		from = ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
+		mch_memmove(from, ip->bw_rest, (size_t)ip->bw_restlen);
+		mch_memmove(from + ip->bw_restlen, buf, (size_t)len);
+	    }
+	    else
+	    {
+		from = buf;
+		fromlen = len;
+	    }
+
+	    to = ip->bw_conv_buf;
+	    if (enc_utf8)
+	    {
+		// Convert from UTF-8 to UCS-2, to the start of the buffer.
+		// The buffer has been allocated to be big enough.
+		while (fromlen > 0)
+		{
+		    n = (int)utf_ptr2len_len(from, (int)fromlen);
+		    if (n > (int)fromlen)	// incomplete byte sequence
+			break;
+		    u8c = utf_ptr2char(from);
+		    *to++ = (u8c & 0xff);
+		    *to++ = (u8c >> 8);
+		    fromlen -= n;
+		    from += n;
+		}
+
+		// Copy remainder to ip->bw_rest[] to be used for the next
+		// call.
+		if (fromlen > CONV_RESTLEN)
+		{
+		    // weird overlong sequence
+		    ip->bw_conv_error = TRUE;
+		    return FAIL;
+		}
+		mch_memmove(ip->bw_rest, from, fromlen);
+		ip->bw_restlen = (int)fromlen;
+	    }
+	    else
+	    {
+		// Convert from enc_codepage to UCS-2, to the start of the
+		// buffer.  The buffer has been allocated to be big enough.
+		ip->bw_restlen = 0;
+		needed = MultiByteToWideChar(enc_codepage,
+			     MB_ERR_INVALID_CHARS, (LPCSTR)from, (int)fromlen,
+								     NULL, 0);
+		if (needed == 0)
+		{
+		    // When conversion fails there may be a trailing byte.
+		    needed = MultiByteToWideChar(enc_codepage,
+			 MB_ERR_INVALID_CHARS, (LPCSTR)from, (int)fromlen - 1,
+								     NULL, 0);
+		    if (needed == 0)
+		    {
+			// Conversion doesn't work.
+			ip->bw_conv_error = TRUE;
+			return FAIL;
+		    }
+		    // Save the trailing byte for the next call.
+		    ip->bw_rest[0] = from[fromlen - 1];
+		    ip->bw_restlen = 1;
+		}
+		needed = MultiByteToWideChar(enc_codepage, MB_ERR_INVALID_CHARS,
+				(LPCSTR)from, (int)(fromlen - ip->bw_restlen),
+							  (LPWSTR)to, needed);
+		if (needed == 0)
+		{
+		    // Safety check: Conversion doesn't work.
+		    ip->bw_conv_error = TRUE;
+		    return FAIL;
+		}
+		to += needed * 2;
+	    }
+
+	    fromlen = to - ip->bw_conv_buf;
+	    buf = to;
+# ifdef CP_UTF8	// VC 4.1 doesn't define CP_UTF8
+	    if (FIO_GET_CP(flags) == CP_UTF8)
+	    {
+		// Convert from UCS-2 to UTF-8, using the remainder of the
+		// conversion buffer.  Fails when out of space.
+		for (from = ip->bw_conv_buf; fromlen > 1; fromlen -= 2)
+		{
+		    u8c = *from++;
+		    u8c += (*from++ << 8);
+		    to += utf_char2bytes(u8c, to);
+		    if (to + 6 >= ip->bw_conv_buf + ip->bw_conv_buflen)
+		    {
+			ip->bw_conv_error = TRUE;
+			return FAIL;
+		    }
+		}
+		len = (int)(to - buf);
+	    }
+	    else
+# endif
+	    {
+		// Convert from UCS-2 to the codepage, using the remainder of
+		// the conversion buffer.  If the conversion uses the default
+		// character "0", the data doesn't fit in this encoding, so
+		// fail.
+		len = WideCharToMultiByte(FIO_GET_CP(flags), 0,
+			(LPCWSTR)ip->bw_conv_buf, (int)fromlen / sizeof(WCHAR),
+			(LPSTR)to, (int)(ip->bw_conv_buflen - fromlen), 0,
+									&bad);
+		if (bad)
+		{
+		    ip->bw_conv_error = TRUE;
+		    return FAIL;
+		}
+	    }
+	}
+#endif
+
+#ifdef MACOS_CONVERT
+	else if (flags & FIO_MACROMAN)
+	{
+	    // Convert UTF-8 or latin1 to Apple MacRoman.
+	    char_u	*from;
+	    size_t	fromlen;
+
+	    if (ip->bw_restlen > 0)
+	    {
+		// Need to concatenate the remainder of the previous call and
+		// the bytes of the current call.  Use the end of the
+		// conversion buffer for this.
+		fromlen = len + ip->bw_restlen;
+		from = ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
+		mch_memmove(from, ip->bw_rest, (size_t)ip->bw_restlen);
+		mch_memmove(from + ip->bw_restlen, buf, (size_t)len);
+	    }
+	    else
+	    {
+		from = buf;
+		fromlen = len;
+	    }
+
+	    if (enc2macroman(from, fromlen,
+			ip->bw_conv_buf, &len, ip->bw_conv_buflen,
+			ip->bw_rest, &ip->bw_restlen) == FAIL)
+	    {
+		ip->bw_conv_error = TRUE;
+		return FAIL;
+	    }
+	    buf = ip->bw_conv_buf;
+	}
+#endif
+
+#ifdef USE_ICONV
+	if (ip->bw_iconv_fd != (iconv_t)-1)
+	{
+	    const char	*from;
+	    size_t	fromlen;
+	    char	*to;
+	    size_t	tolen;
+
+	    // Convert with iconv().
+	    if (ip->bw_restlen > 0)
+	    {
+		char *fp;
+
+		// Need to concatenate the remainder of the previous call and
+		// the bytes of the current call.  Use the end of the
+		// conversion buffer for this.
+		fromlen = len + ip->bw_restlen;
+		fp = (char *)ip->bw_conv_buf + ip->bw_conv_buflen - fromlen;
+		mch_memmove(fp, ip->bw_rest, (size_t)ip->bw_restlen);
+		mch_memmove(fp + ip->bw_restlen, buf, (size_t)len);
+		from = fp;
+		tolen = ip->bw_conv_buflen - fromlen;
+	    }
+	    else
+	    {
+		from = (const char *)buf;
+		fromlen = len;
+		tolen = ip->bw_conv_buflen;
+	    }
+	    to = (char *)ip->bw_conv_buf;
+
+	    if (ip->bw_first)
+	    {
+		size_t	save_len = tolen;
+
+		// output the initial shift state sequence
+		(void)iconv(ip->bw_iconv_fd, NULL, NULL, &to, &tolen);
+
+		// There is a bug in iconv() on Linux (which appears to be
+		// wide-spread) which sets "to" to NULL and messes up "tolen".
+		if (to == NULL)
+		{
+		    to = (char *)ip->bw_conv_buf;
+		    tolen = save_len;
+		}
+		ip->bw_first = FALSE;
+	    }
+
+	    // If iconv() has an error or there is not enough room, fail.
+	    if ((iconv(ip->bw_iconv_fd, (void *)&from, &fromlen, &to, &tolen)
+			== (size_t)-1 && ICONV_ERRNO != ICONV_EINVAL)
+						    || fromlen > CONV_RESTLEN)
+	    {
+		ip->bw_conv_error = TRUE;
+		return FAIL;
+	    }
+
+	    // copy remainder to ip->bw_rest[] to be used for the next call.
+	    if (fromlen > 0)
+		mch_memmove(ip->bw_rest, (void *)from, fromlen);
+	    ip->bw_restlen = (int)fromlen;
+
+	    buf = ip->bw_conv_buf;
+	    len = (int)((char_u *)to - ip->bw_conv_buf);
+	}
+#endif
+    }
+
+    if (ip->bw_fd < 0)
+	// Only checking conversion, which is OK if we get here.
+	return OK;
+
+#ifdef FEAT_CRYPT
+    if (flags & FIO_ENCRYPTED)
+    {
+	// Encrypt the data. Do it in-place if possible, otherwise use an
+	// allocated buffer.
+# ifdef CRYPT_NOT_INPLACE
+	if (crypt_works_inplace(ip->bw_buffer->b_cryptstate))
+	{
+# endif
+	    crypt_encode_inplace(ip->bw_buffer->b_cryptstate, buf, len);
+# ifdef CRYPT_NOT_INPLACE
+	}
+	else
+	{
+	    char_u *outbuf;
+
+	    len = crypt_encode_alloc(curbuf->b_cryptstate, buf, len, &outbuf);
+	    if (len == 0)
+		return OK;  // Crypt layer is buffering, will flush later.
+	    wlen = write_eintr(ip->bw_fd, outbuf, len);
+	    vim_free(outbuf);
+	    return (wlen < len) ? FAIL : OK;
+	}
+# endif
+    }
+#endif
+
+    wlen = write_eintr(ip->bw_fd, buf, len);
+    return (wlen < len) ? FAIL : OK;
+}
+
+/*
+ * Check modification time of file, before writing to it.
+ * The size isn't checked, because using a tool like "gzip" takes care of
+ * using the same timestamp but can't set the size.
+ */
+    static int
+check_mtime(buf_T *buf, stat_T *st)
+{
+    if (buf->b_mtime_read != 0
+	    && time_differs((long)st->st_mtime, buf->b_mtime_read))
+    {
+	msg_scroll = TRUE;	    // don't overwrite messages here
+	msg_silent = 0;		    // must give this prompt
+	// don't use emsg() here, don't want to flush the buffers
+	msg_attr(_("WARNING: The file has been changed since reading it!!!"),
+						       HL_ATTR(HLF_E));
+	if (ask_yesno((char_u *)_("Do you really want to write to it"),
+								 TRUE) == 'n')
+	    return FAIL;
+	msg_scroll = FALSE;	    // always overwrite the file message now
+    }
+    return OK;
+}
+
+/*
+ * Generate a BOM in "buf[4]" for encoding "name".
+ * Return the length of the BOM (zero when no BOM).
+ */
+    static int
+make_bom(char_u *buf, char_u *name)
+{
+    int		flags;
+    char_u	*p;
+
+    flags = get_fio_flags(name);
+
+    // Can't put a BOM in a non-Unicode file.
+    if (flags == FIO_LATIN1 || flags == 0)
+	return 0;
+
+    if (flags == FIO_UTF8)	// UTF-8
+    {
+	buf[0] = 0xef;
+	buf[1] = 0xbb;
+	buf[2] = 0xbf;
+	return 3;
+    }
+    p = buf;
+    (void)ucs2bytes(0xfeff, &p, flags);
+    return (int)(p - buf);
+}
+
+#ifdef UNIX
+    static void
+set_file_time(
+    char_u  *fname,
+    time_t  atime,	    // access time
+    time_t  mtime)	    // modification time
+{
+# if defined(HAVE_UTIME) && defined(HAVE_UTIME_H)
+    struct utimbuf  buf;
+
+    buf.actime	= atime;
+    buf.modtime	= mtime;
+    (void)utime((char *)fname, &buf);
+# else
+#  if defined(HAVE_UTIMES)
+    struct timeval  tvp[2];
+
+    tvp[0].tv_sec   = atime;
+    tvp[0].tv_usec  = 0;
+    tvp[1].tv_sec   = mtime;
+    tvp[1].tv_usec  = 0;
+#   ifdef NeXT
+    (void)utimes((char *)fname, tvp);
+#   else
+    (void)utimes((char *)fname, (const struct timeval *)&tvp);
+#   endif
+#  endif
+# endif
+}
+#endif // UNIX
+
+/*
+ * buf_write() - write to file "fname" lines "start" through "end"
+ *
+ * We do our own buffering here because fwrite() is so slow.
+ *
+ * If "forceit" is true, we don't care for errors when attempting backups.
+ * In case of an error everything possible is done to restore the original
+ * file.  But when "forceit" is TRUE, we risk losing it.
+ *
+ * When "reset_changed" is TRUE and "append" == FALSE and "start" == 1 and
+ * "end" == curbuf->b_ml.ml_line_count, reset curbuf->b_changed.
+ *
+ * This function must NOT use NameBuff (because it's called by autowrite()).
+ *
+ * return FAIL for failure, OK otherwise
+ */
+    int
+buf_write(
+    buf_T	    *buf,
+    char_u	    *fname,
+    char_u	    *sfname,
+    linenr_T	    start,
+    linenr_T	    end,
+    exarg_T	    *eap,		// for forced 'ff' and 'fenc', can be
+					// NULL!
+    int		    append,		// append to the file
+    int		    forceit,
+    int		    reset_changed,
+    int		    filtering)
+{
+    int		    fd;
+    char_u	    *backup = NULL;
+    int		    backup_copy = FALSE; // copy the original file?
+    int		    dobackup;
+    char_u	    *ffname;
+    char_u	    *wfname = NULL;	// name of file to write to
+    char_u	    *s;
+    char_u	    *ptr;
+    char_u	    c;
+    int		    len;
+    linenr_T	    lnum;
+    long	    nchars;
+    char_u	    *errmsg = NULL;
+    int		    errmsg_allocated = FALSE;
+    char_u	    *errnum = NULL;
+    char_u	    *buffer;
+    char_u	    smallbuf[SMALLBUFSIZE];
+    char_u	    *backup_ext;
+    int		    bufsize;
+    long	    perm;		    // file permissions
+    int		    retval = OK;
+    int		    newfile = FALSE;	    // TRUE if file doesn't exist yet
+    int		    msg_save = msg_scroll;
+    int		    overwriting;	    // TRUE if writing over original
+    int		    no_eol = FALSE;	    // no end-of-line written
+    int		    device = FALSE;	    // writing to a device
+    stat_T	    st_old;
+    int		    prev_got_int = got_int;
+    int		    checking_conversion;
+    int		    file_readonly = FALSE;  // overwritten file is read-only
+    static char	    *err_readonly = "is read-only (cannot override: \"W\" in 'cpoptions')";
+#if defined(UNIX)			    // XXX fix me sometime?
+    int		    made_writable = FALSE;  // 'w' bit has been set
+#endif
+					// writing everything
+    int		    whole = (start == 1 && end == buf->b_ml.ml_line_count);
+    linenr_T	    old_line_count = buf->b_ml.ml_line_count;
+    int		    attr;
+    int		    fileformat;
+    int		    write_bin;
+    struct bw_info  write_info;		// info for buf_write_bytes()
+    int		    converted = FALSE;
+    int		    notconverted = FALSE;
+    char_u	    *fenc;		// effective 'fileencoding'
+    char_u	    *fenc_tofree = NULL; // allocated "fenc"
+    int		    wb_flags = 0;
+#ifdef HAVE_ACL
+    vim_acl_T	    acl = NULL;		// ACL copied from original file to
+					// backup or new file
+#endif
+#ifdef FEAT_PERSISTENT_UNDO
+    int		    write_undo_file = FALSE;
+    context_sha256_T sha_ctx;
+#endif
+    unsigned int    bkc = get_bkc_value(buf);
+
+    if (fname == NULL || *fname == NUL)	// safety check
+	return FAIL;
+    if (buf->b_ml.ml_mfp == NULL)
+    {
+	// This can happen during startup when there is a stray "w" in the
+	// vimrc file.
+	emsg(_(e_emptybuf));
+	return FAIL;
+    }
+
+    // Disallow writing from .exrc and .vimrc in current directory for
+    // security reasons.
+    if (check_secure())
+	return FAIL;
+
+    // Avoid a crash for a long name.
+    if (STRLEN(fname) >= MAXPATHL)
+    {
+	emsg(_(e_longname));
+	return FAIL;
+    }
+
+    // must init bw_conv_buf and bw_iconv_fd before jumping to "fail"
+    write_info.bw_conv_buf = NULL;
+    write_info.bw_conv_error = FALSE;
+    write_info.bw_conv_error_lnum = 0;
+    write_info.bw_restlen = 0;
+#ifdef USE_ICONV
+    write_info.bw_iconv_fd = (iconv_t)-1;
+#endif
+#ifdef FEAT_CRYPT
+    write_info.bw_buffer = buf;
+#endif
+
+    // After writing a file changedtick changes but we don't want to display
+    // the line.
+    ex_no_reprint = TRUE;
+
+    // If there is no file name yet, use the one for the written file.
+    // BF_NOTEDITED is set to reflect this (in case the write fails).
+    // Don't do this when the write is for a filter command.
+    // Don't do this when appending.
+    // Only do this when 'cpoptions' contains the 'F' flag.
+    if (buf->b_ffname == NULL
+	    && reset_changed
+	    && whole
+	    && buf == curbuf
+#ifdef FEAT_QUICKFIX
+	    && !bt_nofilename(buf)
+#endif
+	    && !filtering
+	    && (!append || vim_strchr(p_cpo, CPO_FNAMEAPP) != NULL)
+	    && vim_strchr(p_cpo, CPO_FNAMEW) != NULL)
+    {
+	if (set_rw_fname(fname, sfname) == FAIL)
+	    return FAIL;
+	buf = curbuf;	    // just in case autocmds made "buf" invalid
+    }
+
+    if (sfname == NULL)
+	sfname = fname;
+    // For Unix: Use the short file name whenever possible.
+    // Avoids problems with networks and when directory names are changed.
+    // Don't do this for MS-DOS, a "cd" in a sub-shell may have moved us to
+    // another directory, which we don't detect
+    ffname = fname;			    // remember full fname
+#ifdef UNIX
+    fname = sfname;
+#endif
+
+    if (buf->b_ffname != NULL && fnamecmp(ffname, buf->b_ffname) == 0)
+	overwriting = TRUE;
+    else
+	overwriting = FALSE;
+
+    if (exiting)
+	settmode(TMODE_COOK);	    // when exiting allow typeahead now
+
+    ++no_wait_return;		    // don't wait for return yet
+
+    // Set '[ and '] marks to the lines to be written.
+    buf->b_op_start.lnum = start;
+    buf->b_op_start.col = 0;
+    buf->b_op_end.lnum = end;
+    buf->b_op_end.col = 0;
+
+    {
+	aco_save_T	aco;
+	int		buf_ffname = FALSE;
+	int		buf_sfname = FALSE;
+	int		buf_fname_f = FALSE;
+	int		buf_fname_s = FALSE;
+	int		did_cmd = FALSE;
+	int		nofile_err = FALSE;
+	int		empty_memline = (buf->b_ml.ml_mfp == NULL);
+	bufref_T	bufref;
+
+	// Apply PRE autocommands.
+	// Set curbuf to the buffer to be written.
+	// Careful: The autocommands may call buf_write() recursively!
+	if (ffname == buf->b_ffname)
+	    buf_ffname = TRUE;
+	if (sfname == buf->b_sfname)
+	    buf_sfname = TRUE;
+	if (fname == buf->b_ffname)
+	    buf_fname_f = TRUE;
+	if (fname == buf->b_sfname)
+	    buf_fname_s = TRUE;
+
+	// set curwin/curbuf to buf and save a few things
+	aucmd_prepbuf(&aco, buf);
+	set_bufref(&bufref, buf);
+
+	if (append)
+	{
+	    if (!(did_cmd = apply_autocmds_exarg(EVENT_FILEAPPENDCMD,
+					 sfname, sfname, FALSE, curbuf, eap)))
+	    {
+#ifdef FEAT_QUICKFIX
+		if (overwriting && bt_nofilename(curbuf))
+		    nofile_err = TRUE;
+		else
+#endif
+		    apply_autocmds_exarg(EVENT_FILEAPPENDPRE,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    }
+	}
+	else if (filtering)
+	{
+	    apply_autocmds_exarg(EVENT_FILTERWRITEPRE,
+					    NULL, sfname, FALSE, curbuf, eap);
+	}
+	else if (reset_changed && whole)
+	{
+	    int was_changed = curbufIsChanged();
+
+	    did_cmd = apply_autocmds_exarg(EVENT_BUFWRITECMD,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    if (did_cmd)
+	    {
+		if (was_changed && !curbufIsChanged())
+		{
+		    // Written everything correctly and BufWriteCmd has reset
+		    // 'modified': Correct the undo information so that an
+		    // undo now sets 'modified'.
+		    u_unchanged(curbuf);
+		    u_update_save_nr(curbuf);
+		}
+	    }
+	    else
+	    {
+#ifdef FEAT_QUICKFIX
+		if (overwriting && bt_nofilename(curbuf))
+		    nofile_err = TRUE;
+		else
+#endif
+		    apply_autocmds_exarg(EVENT_BUFWRITEPRE,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    }
+	}
+	else
+	{
+	    if (!(did_cmd = apply_autocmds_exarg(EVENT_FILEWRITECMD,
+					 sfname, sfname, FALSE, curbuf, eap)))
+	    {
+#ifdef FEAT_QUICKFIX
+		if (overwriting && bt_nofilename(curbuf))
+		    nofile_err = TRUE;
+		else
+#endif
+		    apply_autocmds_exarg(EVENT_FILEWRITEPRE,
+					  sfname, sfname, FALSE, curbuf, eap);
+	    }
+	}
+
+	// restore curwin/curbuf and a few other things
+	aucmd_restbuf(&aco);
+
+	// In three situations we return here and don't write the file:
+	// 1. the autocommands deleted or unloaded the buffer.
+	// 2. The autocommands abort script processing.
+	// 3. If one of the "Cmd" autocommands was executed.
+	if (!bufref_valid(&bufref))
+	    buf = NULL;
+	if (buf == NULL || (buf->b_ml.ml_mfp == NULL && !empty_memline)
+				       || did_cmd || nofile_err
+#ifdef FEAT_EVAL
+				       || aborting()
+#endif
+				       )
+	{
+	    --no_wait_return;
+	    msg_scroll = msg_save;
+	    if (nofile_err)
+		emsg(_("E676: No matching autocommands for acwrite buffer"));
+
+	    if (nofile_err
+#ifdef FEAT_EVAL
+		    || aborting()
+#endif
+		    )
+		// An aborting error, interrupt or exception in the
+		// autocommands.
+		return FAIL;
+	    if (did_cmd)
+	    {
+		if (buf == NULL)
+		    // The buffer was deleted.  We assume it was written
+		    // (can't retry anyway).
+		    return OK;
+		if (overwriting)
+		{
+		    // Assume the buffer was written, update the timestamp.
+		    ml_timestamp(buf);
+		    if (append)
+			buf->b_flags &= ~BF_NEW;
+		    else
+			buf->b_flags &= ~BF_WRITE_MASK;
+		}
+		if (reset_changed && buf->b_changed && !append
+			&& (overwriting || vim_strchr(p_cpo, CPO_PLUS) != NULL))
+		    // Buffer still changed, the autocommands didn't work
+		    // properly.
+		    return FAIL;
+		return OK;
+	    }
+#ifdef FEAT_EVAL
+	    if (!aborting())
+#endif
+		emsg(_("E203: Autocommands deleted or unloaded buffer to be written"));
+	    return FAIL;
+	}
+
+	// The autocommands may have changed the number of lines in the file.
+	// When writing the whole file, adjust the end.
+	// When writing part of the file, assume that the autocommands only
+	// changed the number of lines that are to be written (tricky!).
+	if (buf->b_ml.ml_line_count != old_line_count)
+	{
+	    if (whole)						// write all
+		end = buf->b_ml.ml_line_count;
+	    else if (buf->b_ml.ml_line_count > old_line_count)	// more lines
+		end += buf->b_ml.ml_line_count - old_line_count;
+	    else						// less lines
+	    {
+		end -= old_line_count - buf->b_ml.ml_line_count;
+		if (end < start)
+		{
+		    --no_wait_return;
+		    msg_scroll = msg_save;
+		    emsg(_("E204: Autocommand changed number of lines in unexpected way"));
+		    return FAIL;
+		}
+	    }
+	}
+
+	// The autocommands may have changed the name of the buffer, which may
+	// be kept in fname, ffname and sfname.
+	if (buf_ffname)
+	    ffname = buf->b_ffname;
+	if (buf_sfname)
+	    sfname = buf->b_sfname;
+	if (buf_fname_f)
+	    fname = buf->b_ffname;
+	if (buf_fname_s)
+	    fname = buf->b_sfname;
+    }
+
+#ifdef FEAT_NETBEANS_INTG
+    if (netbeans_active() && isNetbeansBuffer(buf))
+    {
+	if (whole)
+	{
+	    // b_changed can be 0 after an undo, but we still need to write
+	    // the buffer to NetBeans.
+	    if (buf->b_changed || isNetbeansModified(buf))
+	    {
+		--no_wait_return;		// may wait for return now
+		msg_scroll = msg_save;
+		netbeans_save_buffer(buf);	// no error checking...
+		return retval;
+	    }
+	    else
+	    {
+		errnum = (char_u *)"E656: ";
+		errmsg = (char_u *)_("NetBeans disallows writes of unmodified buffers");
+		buffer = NULL;
+		goto fail;
+	    }
+	}
+	else
+	{
+	    errnum = (char_u *)"E657: ";
+	    errmsg = (char_u *)_("Partial writes disallowed for NetBeans buffers");
+	    buffer = NULL;
+	    goto fail;
+	}
+    }
+#endif
+
+    if (shortmess(SHM_OVER) && !exiting)
+	msg_scroll = FALSE;	    // overwrite previous file message
+    else
+	msg_scroll = TRUE;	    // don't overwrite previous file message
+    if (!filtering)
+	filemess(buf,
+#ifndef UNIX
+		sfname,
+#else
+		fname,
+#endif
+		    (char_u *)"", 0);	// show that we are busy
+    msg_scroll = FALSE;		    // always overwrite the file message now
+
+    buffer = alloc(WRITEBUFSIZE);
+    if (buffer == NULL)		    // can't allocate big buffer, use small
+				    // one (to be able to write when out of
+				    // memory)
+    {
+	buffer = smallbuf;
+	bufsize = SMALLBUFSIZE;
+    }
+    else
+	bufsize = WRITEBUFSIZE;
+
+    // Get information about original file (if there is one).
+#if defined(UNIX)
+    st_old.st_dev = 0;
+    st_old.st_ino = 0;
+    perm = -1;
+    if (mch_stat((char *)fname, &st_old) < 0)
+	newfile = TRUE;
+    else
+    {
+	perm = st_old.st_mode;
+	if (!S_ISREG(st_old.st_mode))		// not a file
+	{
+	    if (S_ISDIR(st_old.st_mode))
+	    {
+		errnum = (char_u *)"E502: ";
+		errmsg = (char_u *)_("is a directory");
+		goto fail;
+	    }
+	    if (mch_nodetype(fname) != NODE_WRITABLE)
+	    {
+		errnum = (char_u *)"E503: ";
+		errmsg = (char_u *)_("is not a file or writable device");
+		goto fail;
+	    }
+	    // It's a device of some kind (or a fifo) which we can write to
+	    // but for which we can't make a backup.
+	    device = TRUE;
+	    newfile = TRUE;
+	    perm = -1;
+	}
+    }
+#else // !UNIX
+    // Check for a writable device name.
+    c = mch_nodetype(fname);
+    if (c == NODE_OTHER)
+    {
+	errnum = (char_u *)"E503: ";
+	errmsg = (char_u *)_("is not a file or writable device");
+	goto fail;
+    }
+    if (c == NODE_WRITABLE)
+    {
+# if defined(MSWIN)
+	// MS-Windows allows opening a device, but we will probably get stuck
+	// trying to write to it.
+	if (!p_odev)
+	{
+	    errnum = (char_u *)"E796: ";
+	    errmsg = (char_u *)_("writing to device disabled with 'opendevice' option");
+	    goto fail;
+	}
+# endif
+	device = TRUE;
+	newfile = TRUE;
+	perm = -1;
+    }
+    else
+    {
+	perm = mch_getperm(fname);
+	if (perm < 0)
+	    newfile = TRUE;
+	else if (mch_isdir(fname))
+	{
+	    errnum = (char_u *)"E502: ";
+	    errmsg = (char_u *)_("is a directory");
+	    goto fail;
+	}
+	if (overwriting)
+	    (void)mch_stat((char *)fname, &st_old);
+    }
+#endif // !UNIX
+
+    if (!device && !newfile)
+    {
+	// Check if the file is really writable (when renaming the file to
+	// make a backup we won't discover it later).
+	file_readonly = check_file_readonly(fname, (int)perm);
+
+	if (!forceit && file_readonly)
+	{
+	    if (vim_strchr(p_cpo, CPO_FWRITE) != NULL)
+	    {
+		errnum = (char_u *)"E504: ";
+		errmsg = (char_u *)_(err_readonly);
+	    }
+	    else
+	    {
+		errnum = (char_u *)"E505: ";
+		errmsg = (char_u *)_("is read-only (add ! to override)");
+	    }
+	    goto fail;
+	}
+
+	// Check if the timestamp hasn't changed since reading the file.
+	if (overwriting)
+	{
+	    retval = check_mtime(buf, &st_old);
+	    if (retval == FAIL)
+		goto fail;
+	}
+    }
+
+#ifdef HAVE_ACL
+    // For systems that support ACL: get the ACL from the original file.
+    if (!newfile)
+	acl = mch_get_acl(fname);
+#endif
+
+    // If 'backupskip' is not empty, don't make a backup for some files.
+    dobackup = (p_wb || p_bk || *p_pm != NUL);
+#ifdef FEAT_WILDIGN
+    if (dobackup && *p_bsk != NUL && match_file_list(p_bsk, sfname, ffname))
+	dobackup = FALSE;
+#endif
+
+    // Save the value of got_int and reset it.  We don't want a previous
+    // interruption cancel writing, only hitting CTRL-C while writing should
+    // abort it.
+    prev_got_int = got_int;
+    got_int = FALSE;
+
+    // Mark the buffer as 'being saved' to prevent changed buffer warnings
+    buf->b_saving = TRUE;
+
+    // If we are not appending or filtering, the file exists, and the
+    // 'writebackup', 'backup' or 'patchmode' option is set, need a backup.
+    // When 'patchmode' is set also make a backup when appending.
+    //
+    // Do not make any backup, if 'writebackup' and 'backup' are both switched
+    // off.  This helps when editing large files on almost-full disks.
+    if (!(append && *p_pm == NUL) && !filtering && perm >= 0 && dobackup)
+    {
+#if defined(UNIX) || defined(MSWIN)
+	stat_T	    st;
+#endif
+
+	if ((bkc & BKC_YES) || append)	// "yes"
+	    backup_copy = TRUE;
+#if defined(UNIX) || defined(MSWIN)
+	else if ((bkc & BKC_AUTO))	// "auto"
+	{
+	    int		i;
+
+# ifdef UNIX
+	    // Don't rename the file when:
+	    // - it's a hard link
+	    // - it's a symbolic link
+	    // - we don't have write permission in the directory
+	    // - we can't set the owner/group of the new file
+	    if (st_old.st_nlink > 1
+		    || mch_lstat((char *)fname, &st) < 0
+		    || st.st_dev != st_old.st_dev
+		    || st.st_ino != st_old.st_ino
+#  ifndef HAVE_FCHOWN
+		    || st.st_uid != st_old.st_uid
+		    || st.st_gid != st_old.st_gid
+#  endif
+		    )
+		backup_copy = TRUE;
+	    else
+# else
+#  ifdef MSWIN
+	    // On NTFS file systems hard links are possible.
+	    if (mch_is_linked(fname))
+		backup_copy = TRUE;
+	    else
+#  endif
+# endif
+	    {
+		// Check if we can create a file and set the owner/group to
+		// the ones from the original file.
+		// First find a file name that doesn't exist yet (use some
+		// arbitrary numbers).
+		STRCPY(IObuff, fname);
+		for (i = 4913; ; i += 123)
+		{
+		    sprintf((char *)gettail(IObuff), "%d", i);
+		    if (mch_lstat((char *)IObuff, &st) < 0)
+			break;
+		}
+		fd = mch_open((char *)IObuff,
+				    O_CREAT|O_WRONLY|O_EXCL|O_NOFOLLOW, perm);
+		if (fd < 0)	// can't write in directory
+		    backup_copy = TRUE;
+		else
+		{
+# ifdef UNIX
+#  ifdef HAVE_FCHOWN
+		    vim_ignored = fchown(fd, st_old.st_uid, st_old.st_gid);
+#  endif
+		    if (mch_stat((char *)IObuff, &st) < 0
+			    || st.st_uid != st_old.st_uid
+			    || st.st_gid != st_old.st_gid
+			    || (long)st.st_mode != perm)
+			backup_copy = TRUE;
+# endif
+		    // Close the file before removing it, on MS-Windows we
+		    // can't delete an open file.
+		    close(fd);
+		    mch_remove(IObuff);
+# ifdef MSWIN
+		    // MS-Windows may trigger a virus scanner to open the
+		    // file, we can't delete it then.  Keep trying for half a
+		    // second.
+		    {
+			int try;
+
+			for (try = 0; try < 10; ++try)
+			{
+			    if (mch_lstat((char *)IObuff, &st) < 0)
+				break;
+			    ui_delay(50L, TRUE);  // wait 50 msec
+			    mch_remove(IObuff);
+			}
+		    }
+# endif
+		}
+	    }
+	}
+
+	// Break symlinks and/or hardlinks if we've been asked to.
+	if ((bkc & BKC_BREAKSYMLINK) || (bkc & BKC_BREAKHARDLINK))
+	{
+# ifdef UNIX
+	    int	lstat_res;
+
+	    lstat_res = mch_lstat((char *)fname, &st);
+
+	    // Symlinks.
+	    if ((bkc & BKC_BREAKSYMLINK)
+		    && lstat_res == 0
+		    && st.st_ino != st_old.st_ino)
+		backup_copy = FALSE;
+
+	    // Hardlinks.
+	    if ((bkc & BKC_BREAKHARDLINK)
+		    && st_old.st_nlink > 1
+		    && (lstat_res != 0 || st.st_ino == st_old.st_ino))
+		backup_copy = FALSE;
+# else
+#  if defined(MSWIN)
+	    // Symlinks.
+	    if ((bkc & BKC_BREAKSYMLINK) && mch_is_symbolic_link(fname))
+		backup_copy = FALSE;
+
+	    // Hardlinks.
+	    if ((bkc & BKC_BREAKHARDLINK) && mch_is_hard_link(fname))
+		backup_copy = FALSE;
+#  endif
+# endif
+	}
+
+#endif
+
+	// make sure we have a valid backup extension to use
+	if (*p_bex == NUL)
+	    backup_ext = (char_u *)".bak";
+	else
+	    backup_ext = p_bex;
+
+	if (backup_copy
+		&& (fd = mch_open((char *)fname, O_RDONLY | O_EXTRA, 0)) >= 0)
+	{
+	    int		bfd;
+	    char_u	*copybuf, *wp;
+	    int		some_error = FALSE;
+	    stat_T	st_new;
+	    char_u	*dirp;
+	    char_u	*rootname;
+#if defined(UNIX) || defined(MSWIN)
+	    char_u      *p;
+#endif
+#if defined(UNIX)
+	    int		did_set_shortname;
+	    mode_t	umask_save;
+#endif
+
+	    copybuf = alloc(WRITEBUFSIZE + 1);
+	    if (copybuf == NULL)
+	    {
+		some_error = TRUE;	    // out of memory
+		goto nobackup;
+	    }
+
+	    // Try to make the backup in each directory in the 'bdir' option.
+	    //
+	    // Unix semantics has it, that we may have a writable file,
+	    // that cannot be recreated with a simple open(..., O_CREAT, ) e.g:
+	    //  - the directory is not writable,
+	    //  - the file may be a symbolic link,
+	    //  - the file may belong to another user/group, etc.
+	    //
+	    // For these reasons, the existing writable file must be truncated
+	    // and reused. Creation of a backup COPY will be attempted.
+	    dirp = p_bdir;
+	    while (*dirp)
+	    {
+#ifdef UNIX
+		st_new.st_ino = 0;
+		st_new.st_dev = 0;
+		st_new.st_gid = 0;
+#endif
+
+		// Isolate one directory name, using an entry in 'bdir'.
+		(void)copy_option_part(&dirp, copybuf, WRITEBUFSIZE, ",");
+
+#if defined(UNIX) || defined(MSWIN)
+		p = copybuf + STRLEN(copybuf);
+		if (after_pathsep(copybuf, p) && p[-1] == p[-2])
+		    // Ends with '//', use full path
+		    if ((p = make_percent_swname(copybuf, fname)) != NULL)
+		    {
+			backup = modname(p, backup_ext, FALSE);
+			vim_free(p);
+		    }
+#endif
+		rootname = get_file_in_dir(fname, copybuf);
+		if (rootname == NULL)
+		{
+		    some_error = TRUE;	    // out of memory
+		    goto nobackup;
+		}
+
+#if defined(UNIX)
+		did_set_shortname = FALSE;
+#endif
+
+		// May try twice if 'shortname' not set.
+		for (;;)
+		{
+		    // Make the backup file name.
+		    if (backup == NULL)
+			backup = buf_modname((buf->b_p_sn || buf->b_shortname),
+						 rootname, backup_ext, FALSE);
+		    if (backup == NULL)
+		    {
+			vim_free(rootname);
+			some_error = TRUE;		// out of memory
+			goto nobackup;
+		    }
+
+		    // Check if backup file already exists.
+		    if (mch_stat((char *)backup, &st_new) >= 0)
+		    {
+#ifdef UNIX
+			// Check if backup file is same as original file.
+			// May happen when modname() gave the same file back.
+			// E.g. silly link, or file name-length reached.
+			// If we don't check here, we either ruin the file
+			// when copying or erase it after writing. jw.
+			if (st_new.st_dev == st_old.st_dev
+					    && st_new.st_ino == st_old.st_ino)
+			{
+			    VIM_CLEAR(backup);	// no backup file to delete
+			    // may try again with 'shortname' set
+			    if (!(buf->b_shortname || buf->b_p_sn))
+			    {
+				buf->b_shortname = TRUE;
+				did_set_shortname = TRUE;
+				continue;
+			    }
+				// setting shortname didn't help
+			    if (did_set_shortname)
+				buf->b_shortname = FALSE;
+			    break;
+			}
+#endif
+
+			// If we are not going to keep the backup file, don't
+			// delete an existing one, try to use another name.
+			// Change one character, just before the extension.
+			if (!p_bk)
+			{
+			    wp = backup + STRLEN(backup) - 1
+							 - STRLEN(backup_ext);
+			    if (wp < backup)	// empty file name ???
+				wp = backup;
+			    *wp = 'z';
+			    while (*wp > 'a'
+				    && mch_stat((char *)backup, &st_new) >= 0)
+				--*wp;
+			    // They all exist??? Must be something wrong.
+			    if (*wp == 'a')
+				VIM_CLEAR(backup);
+			}
+		    }
+		    break;
+		}
+		vim_free(rootname);
+
+		// Try to create the backup file
+		if (backup != NULL)
+		{
+		    // remove old backup, if present
+		    mch_remove(backup);
+		    // Open with O_EXCL to avoid the file being created while
+		    // we were sleeping (symlink hacker attack?). Reset umask
+		    // if possible to avoid mch_setperm() below.
+#ifdef UNIX
+		    umask_save = umask(0);
+#endif
+		    bfd = mch_open((char *)backup,
+				O_WRONLY|O_CREAT|O_EXTRA|O_EXCL|O_NOFOLLOW,
+								 perm & 0777);
+#ifdef UNIX
+		    (void)umask(umask_save);
+#endif
+		    if (bfd < 0)
+			VIM_CLEAR(backup);
+		    else
+		    {
+			// Set file protection same as original file, but
+			// strip s-bit.  Only needed if umask() wasn't used
+			// above.
+#ifndef UNIX
+			(void)mch_setperm(backup, perm & 0777);
+#else
+			// Try to set the group of the backup same as the
+			// original file. If this fails, set the protection
+			// bits for the group same as the protection bits for
+			// others.
+			if (st_new.st_gid != st_old.st_gid
+# ifdef HAVE_FCHOWN  // sequent-ptx lacks fchown()
+				&& fchown(bfd, (uid_t)-1, st_old.st_gid) != 0
+# endif
+						)
+			    mch_setperm(backup,
+					  (perm & 0707) | ((perm & 07) << 3));
+# if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
+			mch_copy_sec(fname, backup);
+# endif
+#endif
+
+			// copy the file.
+			write_info.bw_fd = bfd;
+			write_info.bw_buf = copybuf;
+			write_info.bw_flags = FIO_NOCONVERT;
+			while ((write_info.bw_len = read_eintr(fd, copybuf,
+							    WRITEBUFSIZE)) > 0)
+			{
+			    if (buf_write_bytes(&write_info) == FAIL)
+			    {
+				errmsg = (char_u *)_("E506: Can't write to backup file (add ! to override)");
+				break;
+			    }
+			    ui_breakcheck();
+			    if (got_int)
+			    {
+				errmsg = (char_u *)_(e_interr);
+				break;
+			    }
+			}
+
+			if (close(bfd) < 0 && errmsg == NULL)
+			    errmsg = (char_u *)_("E507: Close error for backup file (add ! to override)");
+			if (write_info.bw_len < 0)
+			    errmsg = (char_u *)_("E508: Can't read file for backup (add ! to override)");
+#ifdef UNIX
+			set_file_time(backup, st_old.st_atime, st_old.st_mtime);
+#endif
+#ifdef HAVE_ACL
+			mch_set_acl(backup, acl);
+#endif
+#if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
+			mch_copy_sec(fname, backup);
+#endif
+			break;
+		    }
+		}
+	    }
+    nobackup:
+	    close(fd);		// ignore errors for closing read file
+	    vim_free(copybuf);
+
+	    if (backup == NULL && errmsg == NULL)
+		errmsg = (char_u *)_("E509: Cannot create backup file (add ! to override)");
+	    // ignore errors when forceit is TRUE
+	    if ((some_error || errmsg != NULL) && !forceit)
+	    {
+		retval = FAIL;
+		goto fail;
+	    }
+	    errmsg = NULL;
+	}
+	else
+	{
+	    char_u	*dirp;
+	    char_u	*p;
+	    char_u	*rootname;
+
+	    // Make a backup by renaming the original file.
+
+	    // If 'cpoptions' includes the "W" flag, we don't want to
+	    // overwrite a read-only file.  But rename may be possible
+	    // anyway, thus we need an extra check here.
+	    if (file_readonly && vim_strchr(p_cpo, CPO_FWRITE) != NULL)
+	    {
+		errnum = (char_u *)"E504: ";
+		errmsg = (char_u *)_(err_readonly);
+		goto fail;
+	    }
+
+	    // Form the backup file name - change path/fo.o.h to
+	    // path/fo.o.h.bak Try all directories in 'backupdir', first one
+	    // that works is used.
+	    dirp = p_bdir;
+	    while (*dirp)
+	    {
+		// Isolate one directory name and make the backup file name.
+		(void)copy_option_part(&dirp, IObuff, IOSIZE, ",");
+
+#if defined(UNIX) || defined(MSWIN)
+		p = IObuff + STRLEN(IObuff);
+		if (after_pathsep(IObuff, p) && p[-1] == p[-2])
+		    // path ends with '//', use full path
+		    if ((p = make_percent_swname(IObuff, fname)) != NULL)
+		    {
+			backup = modname(p, backup_ext, FALSE);
+			vim_free(p);
+		    }
+#endif
+		if (backup == NULL)
+		{
+		    rootname = get_file_in_dir(fname, IObuff);
+		    if (rootname == NULL)
+			backup = NULL;
+		    else
+		    {
+			backup = buf_modname(
+				(buf->b_p_sn || buf->b_shortname),
+						rootname, backup_ext, FALSE);
+			vim_free(rootname);
+		    }
+		}
+
+		if (backup != NULL)
+		{
+		    // If we are not going to keep the backup file, don't
+		    // delete an existing one, try to use another name.
+		    // Change one character, just before the extension.
+		    if (!p_bk && mch_getperm(backup) >= 0)
+		    {
+			p = backup + STRLEN(backup) - 1 - STRLEN(backup_ext);
+			if (p < backup)	// empty file name ???
+			    p = backup;
+			*p = 'z';
+			while (*p > 'a' && mch_getperm(backup) >= 0)
+			    --*p;
+			// They all exist??? Must be something wrong!
+			if (*p == 'a')
+			    VIM_CLEAR(backup);
+		    }
+		}
+		if (backup != NULL)
+		{
+		    // Delete any existing backup and move the current version
+		    // to the backup.	For safety, we don't remove the backup
+		    // until the write has finished successfully. And if the
+		    // 'backup' option is set, leave it around.
+
+		    // If the renaming of the original file to the backup file
+		    // works, quit here.
+		    if (vim_rename(fname, backup) == 0)
+			break;
+
+		    VIM_CLEAR(backup);   // don't do the rename below
+		}
+	    }
+	    if (backup == NULL && !forceit)
+	    {
+		errmsg = (char_u *)_("E510: Can't make backup file (add ! to override)");
+		goto fail;
+	    }
+	}
+    }
+
+#if defined(UNIX)
+    // When using ":w!" and the file was read-only: make it writable
+    if (forceit && perm >= 0 && !(perm & 0200) && st_old.st_uid == getuid()
+				     && vim_strchr(p_cpo, CPO_FWRITE) == NULL)
+    {
+	perm |= 0200;
+	(void)mch_setperm(fname, perm);
+	made_writable = TRUE;
+    }
+#endif
+
+    // When using ":w!" and writing to the current file, 'readonly' makes no
+    // sense, reset it, unless 'Z' appears in 'cpoptions'.
+    if (forceit && overwriting && vim_strchr(p_cpo, CPO_KEEPRO) == NULL)
+    {
+	buf->b_p_ro = FALSE;
+#ifdef FEAT_TITLE
+	need_maketitle = TRUE;	    // set window title later
+#endif
+	status_redraw_all();	    // redraw status lines later
+    }
+
+    if (end > buf->b_ml.ml_line_count)
+	end = buf->b_ml.ml_line_count;
+    if (buf->b_ml.ml_flags & ML_EMPTY)
+	start = end + 1;
+
+    // If the original file is being overwritten, there is a small chance that
+    // we crash in the middle of writing. Therefore the file is preserved now.
+    // This makes all block numbers positive so that recovery does not need
+    // the original file.
+    // Don't do this if there is a backup file and we are exiting.
+    if (reset_changed && !newfile && overwriting
+					      && !(exiting && backup != NULL))
+    {
+	ml_preserve(buf, FALSE);
+	if (got_int)
+	{
+	    errmsg = (char_u *)_(e_interr);
+	    goto restore_backup;
+	}
+    }
+
+#ifdef VMS
+    vms_remove_version(fname); // remove version
+#endif
+    // Default: write the file directly.  May write to a temp file for
+    // multi-byte conversion.
+    wfname = fname;
+
+    // Check for forced 'fileencoding' from "++opt=val" argument.
+    if (eap != NULL && eap->force_enc != 0)
+    {
+	fenc = eap->cmd + eap->force_enc;
+	fenc = enc_canonize(fenc);
+	fenc_tofree = fenc;
+    }
+    else
+	fenc = buf->b_p_fenc;
+
+    // Check if the file needs to be converted.
+    converted = need_conversion(fenc);
+
+    // Check if UTF-8 to UCS-2/4 or Latin1 conversion needs to be done.  Or
+    // Latin1 to Unicode conversion.  This is handled in buf_write_bytes().
+    // Prepare the flags for it and allocate bw_conv_buf when needed.
+    if (converted && (enc_utf8 || STRCMP(p_enc, "latin1") == 0))
+    {
+	wb_flags = get_fio_flags(fenc);
+	if (wb_flags & (FIO_UCS2 | FIO_UCS4 | FIO_UTF16 | FIO_UTF8))
+	{
+	    // Need to allocate a buffer to translate into.
+	    if (wb_flags & (FIO_UCS2 | FIO_UTF16 | FIO_UTF8))
+		write_info.bw_conv_buflen = bufsize * 2;
+	    else // FIO_UCS4
+		write_info.bw_conv_buflen = bufsize * 4;
+	    write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
+	    if (write_info.bw_conv_buf == NULL)
+		end = 0;
+	}
+    }
+
+#ifdef MSWIN
+    if (converted && wb_flags == 0 && (wb_flags = get_win_fio_flags(fenc)) != 0)
+    {
+	// Convert UTF-8 -> UCS-2 and UCS-2 -> DBCS.  Worst-case * 4:
+	write_info.bw_conv_buflen = bufsize * 4;
+	write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
+	if (write_info.bw_conv_buf == NULL)
+	    end = 0;
+    }
+#endif
+
+#ifdef MACOS_CONVERT
+    if (converted && wb_flags == 0 && (wb_flags = get_mac_fio_flags(fenc)) != 0)
+    {
+	write_info.bw_conv_buflen = bufsize * 3;
+	write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
+	if (write_info.bw_conv_buf == NULL)
+	    end = 0;
+    }
+#endif
+
+#if defined(FEAT_EVAL) || defined(USE_ICONV)
+    if (converted && wb_flags == 0)
+    {
+# ifdef USE_ICONV
+	// Use iconv() conversion when conversion is needed and it's not done
+	// internally.
+	write_info.bw_iconv_fd = (iconv_t)my_iconv_open(fenc,
+					enc_utf8 ? (char_u *)"utf-8" : p_enc);
+	if (write_info.bw_iconv_fd != (iconv_t)-1)
+	{
+	    // We're going to use iconv(), allocate a buffer to convert in.
+	    write_info.bw_conv_buflen = bufsize * ICONV_MULT;
+	    write_info.bw_conv_buf = alloc(write_info.bw_conv_buflen);
+	    if (write_info.bw_conv_buf == NULL)
+		end = 0;
+	    write_info.bw_first = TRUE;
+	}
+#  ifdef FEAT_EVAL
+	else
+#  endif
+# endif
+
+# ifdef FEAT_EVAL
+	    // When the file needs to be converted with 'charconvert' after
+	    // writing, write to a temp file instead and let the conversion
+	    // overwrite the original file.
+	    if (*p_ccv != NUL)
+	    {
+		wfname = vim_tempname('w', FALSE);
+		if (wfname == NULL)	// Can't write without a tempfile!
+		{
+		    errmsg = (char_u *)_("E214: Can't find temp file for writing");
+		    goto restore_backup;
+		}
+	    }
+# endif
+    }
+#endif
+    if (converted && wb_flags == 0
+#ifdef USE_ICONV
+	    && write_info.bw_iconv_fd == (iconv_t)-1
+# endif
+# ifdef FEAT_EVAL
+	    && wfname == fname
+# endif
+	    )
+    {
+	if (!forceit)
+	{
+	    errmsg = (char_u *)_("E213: Cannot convert (add ! to write without conversion)");
+	    goto restore_backup;
+	}
+	notconverted = TRUE;
+    }
+
+    // If conversion is taking place, we may first pretend to write and check
+    // for conversion errors.  Then loop again to write for real.
+    // When not doing conversion this writes for real right away.
+    for (checking_conversion = TRUE; ; checking_conversion = FALSE)
+    {
+	// There is no need to check conversion when:
+	// - there is no conversion
+	// - we make a backup file, that can be restored in case of conversion
+	//   failure.
+	if (!converted || dobackup)
+	    checking_conversion = FALSE;
+
+	if (checking_conversion)
+	{
+	    // Make sure we don't write anything.
+	    fd = -1;
+	    write_info.bw_fd = fd;
+	}
+	else
+	{
+#ifdef HAVE_FTRUNCATE
+# define TRUNC_ON_OPEN 0
+#else
+# define TRUNC_ON_OPEN O_TRUNC
+#endif
+	    // Open the file "wfname" for writing.
+	    // We may try to open the file twice: If we can't write to the file
+	    // and forceit is TRUE we delete the existing file and try to
+	    // create a new one. If this still fails we may have lost the
+	    // original file!  (this may happen when the user reached his
+	    // quotum for number of files).
+	    // Appending will fail if the file does not exist and forceit is
+	    // FALSE.
+	    while ((fd = mch_open((char *)wfname, O_WRONLY | O_EXTRA | (append
+				? (forceit ? (O_APPEND | O_CREAT) : O_APPEND)
+				: (O_CREAT | TRUNC_ON_OPEN))
+				, perm < 0 ? 0666 : (perm & 0777))) < 0)
+	    {
+		// A forced write will try to create a new file if the old one
+		// is still readonly. This may also happen when the directory
+		// is read-only. In that case the mch_remove() will fail.
+		if (errmsg == NULL)
+		{
+#ifdef UNIX
+		    stat_T	st;
+
+		    // Don't delete the file when it's a hard or symbolic link.
+		    if ((!newfile && st_old.st_nlink > 1)
+			    || (mch_lstat((char *)fname, &st) == 0
+				&& (st.st_dev != st_old.st_dev
+				    || st.st_ino != st_old.st_ino)))
+			errmsg = (char_u *)_("E166: Can't open linked file for writing");
+		    else
+#endif
+		    {
+			errmsg = (char_u *)_("E212: Can't open file for writing");
+			if (forceit && vim_strchr(p_cpo, CPO_FWRITE) == NULL
+								  && perm >= 0)
+			{
+#ifdef UNIX
+			    // we write to the file, thus it should be marked
+			    // writable after all
+			    if (!(perm & 0200))
+				made_writable = TRUE;
+			    perm |= 0200;
+			    if (st_old.st_uid != getuid()
+						  || st_old.st_gid != getgid())
+				perm &= 0777;
+#endif
+			    if (!append)  // don't remove when appending
+				mch_remove(wfname);
+			    continue;
+			}
+		    }
+		}
+
+restore_backup:
+		{
+		    stat_T	st;
+
+		    // If we failed to open the file, we don't need a backup.
+		    // Throw it away.  If we moved or removed the original file
+		    // try to put the backup in its place.
+		    if (backup != NULL && wfname == fname)
+		    {
+			if (backup_copy)
+			{
+			    // There is a small chance that we removed the
+			    // original, try to move the copy in its place.
+			    // This may not work if the vim_rename() fails.
+			    // In that case we leave the copy around.
+
+			    // If file does not exist, put the copy in its
+			    // place
+			    if (mch_stat((char *)fname, &st) < 0)
+				vim_rename(backup, fname);
+			    // if original file does exist throw away the copy
+			    if (mch_stat((char *)fname, &st) >= 0)
+				mch_remove(backup);
+			}
+			else
+			{
+			    // try to put the original file back
+			    vim_rename(backup, fname);
+			}
+		    }
+
+		    // if original file no longer exists give an extra warning
+		    if (!newfile && mch_stat((char *)fname, &st) < 0)
+			end = 0;
+		}
+
+		if (wfname != fname)
+		    vim_free(wfname);
+		goto fail;
+	    }
+	    write_info.bw_fd = fd;
+
+#if defined(UNIX)
+	    {
+		stat_T	st;
+
+		// Double check we are writing the intended file before making
+		// any changes.
+		if (overwriting
+			&& (!dobackup || backup_copy)
+			&& fname == wfname
+			&& perm >= 0
+			&& mch_fstat(fd, &st) == 0
+			&& st.st_ino != st_old.st_ino)
+		{
+		    close(fd);
+		    errmsg = (char_u *)_("E949: File changed while writing");
+		    goto fail;
+		}
+	    }
+#endif
+#ifdef HAVE_FTRUNCATE
+	    if (!append)
+		vim_ignored = ftruncate(fd, (off_t)0);
+#endif
+
+#if defined(MSWIN)
+	    if (backup != NULL && overwriting && !append)
+	    {
+		if (backup_copy)
+		    (void)mch_copy_file_attribute(wfname, backup);
+		else
+		    (void)mch_copy_file_attribute(backup, wfname);
+	    }
+
+	    if (!overwriting && !append)
+	    {
+		if (buf->b_ffname != NULL)
+		    (void)mch_copy_file_attribute(buf->b_ffname, wfname);
+		// Should copy resource fork
+	    }
+#endif
+
+#ifdef FEAT_CRYPT
+	    if (*buf->b_p_key != NUL && !filtering)
+	    {
+		char_u		*header;
+		int		header_len;
+
+		buf->b_cryptstate = crypt_create_for_writing(
+						      crypt_get_method_nr(buf),
+					   buf->b_p_key, &header, &header_len);
+		if (buf->b_cryptstate == NULL || header == NULL)
+		    end = 0;
+		else
+		{
+		    // Write magic number, so that Vim knows how this file is
+		    // encrypted when reading it back.
+		    write_info.bw_buf = header;
+		    write_info.bw_len = header_len;
+		    write_info.bw_flags = FIO_NOCONVERT;
+		    if (buf_write_bytes(&write_info) == FAIL)
+			end = 0;
+		    wb_flags |= FIO_ENCRYPTED;
+		    vim_free(header);
+		}
+	    }
+#endif
+	}
+	errmsg = NULL;
+
+	write_info.bw_buf = buffer;
+	nchars = 0;
+
+	// use "++bin", "++nobin" or 'binary'
+	if (eap != NULL && eap->force_bin != 0)
+	    write_bin = (eap->force_bin == FORCE_BIN);
+	else
+	    write_bin = buf->b_p_bin;
+
+	// The BOM is written just after the encryption magic number.
+	// Skip it when appending and the file already existed, the BOM only
+	// makes sense at the start of the file.
+	if (buf->b_p_bomb && !write_bin && (!append || perm < 0))
+	{
+	    write_info.bw_len = make_bom(buffer, fenc);
+	    if (write_info.bw_len > 0)
+	    {
+		// don't convert, do encryption
+		write_info.bw_flags = FIO_NOCONVERT | wb_flags;
+		if (buf_write_bytes(&write_info) == FAIL)
+		    end = 0;
+		else
+		    nchars += write_info.bw_len;
+	    }
+	}
+	write_info.bw_start_lnum = start;
+
+#ifdef FEAT_PERSISTENT_UNDO
+	write_undo_file = (buf->b_p_udf
+			    && overwriting
+			    && !append
+			    && !filtering
+			    && reset_changed
+			    && !checking_conversion);
+	if (write_undo_file)
+	    // Prepare for computing the hash value of the text.
+	    sha256_start(&sha_ctx);
+#endif
+
+	write_info.bw_len = bufsize;
+	write_info.bw_flags = wb_flags;
+	fileformat = get_fileformat_force(buf, eap);
+	s = buffer;
+	len = 0;
+	for (lnum = start; lnum <= end; ++lnum)
+	{
+	    // The next while loop is done once for each character written.
+	    // Keep it fast!
+	    ptr = ml_get_buf(buf, lnum, FALSE) - 1;
+#ifdef FEAT_PERSISTENT_UNDO
+	    if (write_undo_file)
+		sha256_update(&sha_ctx, ptr + 1,
+					      (UINT32_T)(STRLEN(ptr + 1) + 1));
+#endif
+	    while ((c = *++ptr) != NUL)
+	    {
+		if (c == NL)
+		    *s = NUL;		// replace newlines with NULs
+		else if (c == CAR && fileformat == EOL_MAC)
+		    *s = NL;		// Mac: replace CRs with NLs
+		else
+		    *s = c;
+		++s;
+		if (++len != bufsize)
+		    continue;
+		if (buf_write_bytes(&write_info) == FAIL)
+		{
+		    end = 0;		// write error: break loop
+		    break;
+		}
+		nchars += bufsize;
+		s = buffer;
+		len = 0;
+		write_info.bw_start_lnum = lnum;
+	    }
+	    // write failed or last line has no EOL: stop here
+	    if (end == 0
+		    || (lnum == end
+			&& (write_bin || !buf->b_p_fixeol)
+			&& (lnum == buf->b_no_eol_lnum
+			    || (lnum == buf->b_ml.ml_line_count
+							   && !buf->b_p_eol))))
+	    {
+		++lnum;			// written the line, count it
+		no_eol = TRUE;
+		break;
+	    }
+	    if (fileformat == EOL_UNIX)
+		*s++ = NL;
+	    else
+	    {
+		*s++ = CAR;		    // EOL_MAC or EOL_DOS: write CR
+		if (fileformat == EOL_DOS)  // write CR-NL
+		{
+		    if (++len == bufsize)
+		    {
+			if (buf_write_bytes(&write_info) == FAIL)
+			{
+			    end = 0;	// write error: break loop
+			    break;
+			}
+			nchars += bufsize;
+			s = buffer;
+			len = 0;
+		    }
+		    *s++ = NL;
+		}
+	    }
+	    if (++len == bufsize && end)
+	    {
+		if (buf_write_bytes(&write_info) == FAIL)
+		{
+		    end = 0;		// write error: break loop
+		    break;
+		}
+		nchars += bufsize;
+		s = buffer;
+		len = 0;
+
+		ui_breakcheck();
+		if (got_int)
+		{
+		    end = 0;		// Interrupted, break loop
+		    break;
+		}
+	    }
+#ifdef VMS
+	    // On VMS there is a problem: newlines get added when writing
+	    // blocks at a time. Fix it by writing a line at a time.
+	    // This is much slower!
+	    // Explanation: VAX/DECC RTL insists that records in some RMS
+	    // structures end with a newline (carriage return) character, and
+	    // if they don't it adds one.
+	    // With other RMS structures it works perfect without this fix.
+	    if (buf->b_fab_rfm == FAB$C_VFC
+		    || ((buf->b_fab_rat & (FAB$M_FTN | FAB$M_CR)) != 0))
+	    {
+		int b2write;
+
+		buf->b_fab_mrs = (buf->b_fab_mrs == 0
+			? MIN(4096, bufsize)
+			: MIN(buf->b_fab_mrs, bufsize));
+
+		b2write = len;
+		while (b2write > 0)
+		{
+		    write_info.bw_len = MIN(b2write, buf->b_fab_mrs);
+		    if (buf_write_bytes(&write_info) == FAIL)
+		    {
+			end = 0;
+			break;
+		    }
+		    b2write -= MIN(b2write, buf->b_fab_mrs);
+		}
+		write_info.bw_len = bufsize;
+		nchars += len;
+		s = buffer;
+		len = 0;
+	    }
+#endif
+	}
+	if (len > 0 && end > 0)
+	{
+	    write_info.bw_len = len;
+	    if (buf_write_bytes(&write_info) == FAIL)
+		end = 0;		    // write error
+	    nchars += len;
+	}
+
+	// Stop when writing done or an error was encountered.
+	if (!checking_conversion || end == 0)
+	    break;
+
+	// If no error happened until now, writing should be ok, so loop to
+	// really write the buffer.
+    }
+
+    // If we started writing, finish writing. Also when an error was
+    // encountered.
+    if (!checking_conversion)
+    {
+#if defined(UNIX) && defined(HAVE_FSYNC)
+	// On many journalling file systems there is a bug that causes both the
+	// original and the backup file to be lost when halting the system
+	// right after writing the file.  That's because only the meta-data is
+	// journalled.  Syncing the file slows down the system, but assures it
+	// has been written to disk and we don't lose it.
+	// For a device do try the fsync() but don't complain if it does not
+	// work (could be a pipe).
+	// If the 'fsync' option is FALSE, don't fsync().  Useful for laptops.
+	if (p_fs && vim_fsync(fd) != 0 && !device)
+	{
+	    errmsg = (char_u *)_(e_fsync);
+	    end = 0;
+	}
+#endif
+
+#if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
+	// Probably need to set the security context.
+	if (!backup_copy)
+	    mch_copy_sec(backup, wfname);
+#endif
+
+#ifdef UNIX
+	// When creating a new file, set its owner/group to that of the
+	// original file.  Get the new device and inode number.
+	if (backup != NULL && !backup_copy)
+	{
+# ifdef HAVE_FCHOWN
+	    stat_T	st;
+
+	    // Don't change the owner when it's already OK, some systems remove
+	    // permission or ACL stuff.
+	    if (mch_stat((char *)wfname, &st) < 0
+		    || st.st_uid != st_old.st_uid
+		    || st.st_gid != st_old.st_gid)
+	    {
+		// changing owner might not be possible
+		vim_ignored = fchown(fd, st_old.st_uid, -1);
+		// if changing group fails clear the group permissions
+		if (fchown(fd, -1, st_old.st_gid) == -1 && perm > 0)
+		    perm &= ~070;
+	    }
+# endif
+	    buf_setino(buf);
+	}
+	else if (!buf->b_dev_valid)
+	    // Set the inode when creating a new file.
+	    buf_setino(buf);
+#endif
+
+#ifdef UNIX
+	if (made_writable)
+	    perm &= ~0200;	// reset 'w' bit for security reasons
+#endif
+#ifdef HAVE_FCHMOD
+	// set permission of new file same as old file
+	if (perm >= 0)
+	    (void)mch_fsetperm(fd, perm);
+#endif
+	if (close(fd) != 0)
+	{
+	    errmsg = (char_u *)_("E512: Close failed");
+	    end = 0;
+	}
+
+#ifndef HAVE_FCHMOD
+	// set permission of new file same as old file
+	if (perm >= 0)
+	    (void)mch_setperm(wfname, perm);
+#endif
+#ifdef HAVE_ACL
+	// Probably need to set the ACL before changing the user (can't set the
+	// ACL on a file the user doesn't own).
+	// On Solaris, with ZFS and the aclmode property set to "discard" (the
+	// default), chmod() discards all part of a file's ACL that don't
+	// represent the mode of the file.  It's non-trivial for us to discover
+	// whether we're in that situation, so we simply always re-set the ACL.
+# ifndef HAVE_SOLARIS_ZFS_ACL
+	if (!backup_copy)
+# endif
+	    mch_set_acl(wfname, acl);
+#endif
+#ifdef FEAT_CRYPT
+	if (buf->b_cryptstate != NULL)
+	{
+	    crypt_free_state(buf->b_cryptstate);
+	    buf->b_cryptstate = NULL;
+	}
+#endif
+
+#if defined(FEAT_EVAL)
+	if (wfname != fname)
+	{
+	    // The file was written to a temp file, now it needs to be
+	    // converted with 'charconvert' to (overwrite) the output file.
+	    if (end != 0)
+	    {
+		if (eval_charconvert(enc_utf8 ? (char_u *)"utf-8" : p_enc,
+						  fenc, wfname, fname) == FAIL)
+		{
+		    write_info.bw_conv_error = TRUE;
+		    end = 0;
+		}
+	    }
+	    mch_remove(wfname);
+	    vim_free(wfname);
+	}
+#endif
+    }
+
+    if (end == 0)
+    {
+	// Error encountered.
+	if (errmsg == NULL)
+	{
+	    if (write_info.bw_conv_error)
+	    {
+		if (write_info.bw_conv_error_lnum == 0)
+		    errmsg = (char_u *)_("E513: write error, conversion failed (make 'fenc' empty to override)");
+		else
+		{
+		    errmsg_allocated = TRUE;
+		    errmsg = alloc(300);
+		    vim_snprintf((char *)errmsg, 300, _("E513: write error, conversion failed in line %ld (make 'fenc' empty to override)"),
+					 (long)write_info.bw_conv_error_lnum);
+		}
+	    }
+	    else if (got_int)
+		errmsg = (char_u *)_(e_interr);
+	    else
+		errmsg = (char_u *)_("E514: write error (file system full?)");
+	}
+
+	// If we have a backup file, try to put it in place of the new file,
+	// because the new file is probably corrupt.  This avoids losing the
+	// original file when trying to make a backup when writing the file a
+	// second time.
+	// When "backup_copy" is set we need to copy the backup over the new
+	// file.  Otherwise rename the backup file.
+	// If this is OK, don't give the extra warning message.
+	if (backup != NULL)
+	{
+	    if (backup_copy)
+	    {
+		// This may take a while, if we were interrupted let the user
+		// know we got the message.
+		if (got_int)
+		{
+		    msg(_(e_interr));
+		    out_flush();
+		}
+		if ((fd = mch_open((char *)backup, O_RDONLY | O_EXTRA, 0)) >= 0)
+		{
+		    if ((write_info.bw_fd = mch_open((char *)fname,
+				    O_WRONLY | O_CREAT | O_TRUNC | O_EXTRA,
+							   perm & 0777)) >= 0)
+		    {
+			// copy the file.
+			write_info.bw_buf = smallbuf;
+			write_info.bw_flags = FIO_NOCONVERT;
+			while ((write_info.bw_len = read_eintr(fd, smallbuf,
+						      SMALLBUFSIZE)) > 0)
+			    if (buf_write_bytes(&write_info) == FAIL)
+				break;
+
+			if (close(write_info.bw_fd) >= 0
+						   && write_info.bw_len == 0)
+			    end = 1;		// success
+		    }
+		    close(fd);	// ignore errors for closing read file
+		}
+	    }
+	    else
+	    {
+		if (vim_rename(backup, fname) == 0)
+		    end = 1;
+	    }
+	}
+	goto fail;
+    }
+
+    lnum -= start;	    // compute number of written lines
+    --no_wait_return;	    // may wait for return now
+
+#if !(defined(UNIX) || defined(VMS))
+    fname = sfname;	    // use shortname now, for the messages
+#endif
+    if (!filtering)
+    {
+	msg_add_fname(buf, fname);	// put fname in IObuff with quotes
+	c = FALSE;
+	if (write_info.bw_conv_error)
+	{
+	    STRCAT(IObuff, _(" CONVERSION ERROR"));
+	    c = TRUE;
+	    if (write_info.bw_conv_error_lnum != 0)
+		vim_snprintf_add((char *)IObuff, IOSIZE, _(" in line %ld;"),
+			(long)write_info.bw_conv_error_lnum);
+	}
+	else if (notconverted)
+	{
+	    STRCAT(IObuff, _("[NOT converted]"));
+	    c = TRUE;
+	}
+	else if (converted)
+	{
+	    STRCAT(IObuff, _("[converted]"));
+	    c = TRUE;
+	}
+	if (device)
+	{
+	    STRCAT(IObuff, _("[Device]"));
+	    c = TRUE;
+	}
+	else if (newfile)
+	{
+	    STRCAT(IObuff, shortmess(SHM_NEW) ? _("[New]") : _("[New File]"));
+	    c = TRUE;
+	}
+	if (no_eol)
+	{
+	    msg_add_eol();
+	    c = TRUE;
+	}
+	// may add [unix/dos/mac]
+	if (msg_add_fileformat(fileformat))
+	    c = TRUE;
+#ifdef FEAT_CRYPT
+	if (wb_flags & FIO_ENCRYPTED)
+	{
+	    crypt_append_msg(buf);
+	    c = TRUE;
+	}
+#endif
+	msg_add_lines(c, (long)lnum, nchars);	// add line/char count
+	if (!shortmess(SHM_WRITE))
+	{
+	    if (append)
+		STRCAT(IObuff, shortmess(SHM_WRI) ? _(" [a]") : _(" appended"));
+	    else
+		STRCAT(IObuff, shortmess(SHM_WRI) ? _(" [w]") : _(" written"));
+	}
+
+	set_keep_msg((char_u *)msg_trunc_attr((char *)IObuff, FALSE, 0), 0);
+    }
+
+    // When written everything correctly: reset 'modified'.  Unless not
+    // writing to the original file and '+' is not in 'cpoptions'.
+    if (reset_changed && whole && !append
+	    && !write_info.bw_conv_error
+	    && (overwriting || vim_strchr(p_cpo, CPO_PLUS) != NULL))
+    {
+	unchanged(buf, TRUE, FALSE);
+	// b:changedtick is may be incremented in unchanged() but that
+	// should not trigger a TextChanged event.
+	if (buf->b_last_changedtick + 1 == CHANGEDTICK(buf))
+	    buf->b_last_changedtick = CHANGEDTICK(buf);
+	u_unchanged(buf);
+	u_update_save_nr(buf);
+    }
+
+    // If written to the current file, update the timestamp of the swap file
+    // and reset the BF_WRITE_MASK flags. Also sets buf->b_mtime.
+    if (overwriting)
+    {
+	ml_timestamp(buf);
+	if (append)
+	    buf->b_flags &= ~BF_NEW;
+	else
+	    buf->b_flags &= ~BF_WRITE_MASK;
+    }
+
+    // If we kept a backup until now, and we are in patch mode, then we make
+    // the backup file our 'original' file.
+    if (*p_pm && dobackup)
+    {
+	char *org = (char *)buf_modname((buf->b_p_sn || buf->b_shortname),
+							  fname, p_pm, FALSE);
+
+	if (backup != NULL)
+	{
+	    stat_T	st;
+
+	    // If the original file does not exist yet
+	    // the current backup file becomes the original file
+	    if (org == NULL)
+		emsg(_("E205: Patchmode: can't save original file"));
+	    else if (mch_stat(org, &st) < 0)
+	    {
+		vim_rename(backup, (char_u *)org);
+		VIM_CLEAR(backup);	    // don't delete the file
+#ifdef UNIX
+		set_file_time((char_u *)org, st_old.st_atime, st_old.st_mtime);
+#endif
+	    }
+	}
+	// If there is no backup file, remember that a (new) file was
+	// created.
+	else
+	{
+	    int empty_fd;
+
+	    if (org == NULL
+		    || (empty_fd = mch_open(org,
+				      O_CREAT | O_EXTRA | O_EXCL | O_NOFOLLOW,
+					perm < 0 ? 0666 : (perm & 0777))) < 0)
+	      emsg(_("E206: patchmode: can't touch empty original file"));
+	    else
+	      close(empty_fd);
+	}
+	if (org != NULL)
+	{
+	    mch_setperm((char_u *)org, mch_getperm(fname) & 0777);
+	    vim_free(org);
+	}
+    }
+
+    // Remove the backup unless 'backup' option is set or there was a
+    // conversion error.
+    if (!p_bk && backup != NULL && !write_info.bw_conv_error
+	    && mch_remove(backup) != 0)
+	emsg(_("E207: Can't delete backup file"));
+
+    goto nofail;
+
+    // Finish up.  We get here either after failure or success.
+fail:
+    --no_wait_return;		// may wait for return now
+nofail:
+
+    // Done saving, we accept changed buffer warnings again
+    buf->b_saving = FALSE;
+
+    vim_free(backup);
+    if (buffer != smallbuf)
+	vim_free(buffer);
+    vim_free(fenc_tofree);
+    vim_free(write_info.bw_conv_buf);
+#ifdef USE_ICONV
+    if (write_info.bw_iconv_fd != (iconv_t)-1)
+    {
+	iconv_close(write_info.bw_iconv_fd);
+	write_info.bw_iconv_fd = (iconv_t)-1;
+    }
+#endif
+#ifdef HAVE_ACL
+    mch_free_acl(acl);
+#endif
+
+    if (errmsg != NULL)
+    {
+	int numlen = errnum != NULL ? (int)STRLEN(errnum) : 0;
+
+	attr = HL_ATTR(HLF_E);	// set highlight for error messages
+	msg_add_fname(buf,
+#ifndef UNIX
+		sfname
+#else
+		fname
+#endif
+		     );		// put file name in IObuff with quotes
+	if (STRLEN(IObuff) + STRLEN(errmsg) + numlen >= IOSIZE)
+	    IObuff[IOSIZE - STRLEN(errmsg) - numlen - 1] = NUL;
+	// If the error message has the form "is ...", put the error number in
+	// front of the file name.
+	if (errnum != NULL)
+	{
+	    STRMOVE(IObuff + numlen, IObuff);
+	    mch_memmove(IObuff, errnum, (size_t)numlen);
+	}
+	STRCAT(IObuff, errmsg);
+	emsg((char *)IObuff);
+	if (errmsg_allocated)
+	    vim_free(errmsg);
+
+	retval = FAIL;
+	if (end == 0)
+	{
+	    msg_puts_attr(_("\nWARNING: Original file may be lost or damaged\n"),
+		    attr | MSG_HIST);
+	    msg_puts_attr(_("don't quit the editor until the file is successfully written!"),
+		    attr | MSG_HIST);
+
+	    // Update the timestamp to avoid an "overwrite changed file"
+	    // prompt when writing again.
+	    if (mch_stat((char *)fname, &st_old) >= 0)
+	    {
+		buf_store_time(buf, &st_old, fname);
+		buf->b_mtime_read = buf->b_mtime;
+	    }
+	}
+    }
+    msg_scroll = msg_save;
+
+#ifdef FEAT_PERSISTENT_UNDO
+    // When writing the whole file and 'undofile' is set, also write the undo
+    // file.
+    if (retval == OK && write_undo_file)
+    {
+	char_u	    hash[UNDO_HASH_SIZE];
+
+	sha256_finish(&sha_ctx, hash);
+	u_write_undo(NULL, FALSE, buf, hash);
+    }
+#endif
+
+#ifdef FEAT_EVAL
+    if (!should_abort(retval))
+#else
+    if (!got_int)
+#endif
+    {
+	aco_save_T	aco;
+
+	curbuf->b_no_eol_lnum = 0;  // in case it was set by the previous read
+
+	// Apply POST autocommands.
+	// Careful: The autocommands may call buf_write() recursively!
+	aucmd_prepbuf(&aco, buf);
+
+	if (append)
+	    apply_autocmds_exarg(EVENT_FILEAPPENDPOST, fname, fname,
+							  FALSE, curbuf, eap);
+	else if (filtering)
+	    apply_autocmds_exarg(EVENT_FILTERWRITEPOST, NULL, fname,
+							  FALSE, curbuf, eap);
+	else if (reset_changed && whole)
+	    apply_autocmds_exarg(EVENT_BUFWRITEPOST, fname, fname,
+							  FALSE, curbuf, eap);
+	else
+	    apply_autocmds_exarg(EVENT_FILEWRITEPOST, fname, fname,
+							  FALSE, curbuf, eap);
+
+	// restore curwin/curbuf and a few other things
+	aucmd_restbuf(&aco);
+
+#ifdef FEAT_EVAL
+	if (aborting())	    // autocmds may abort script processing
+	    retval = FALSE;
+#endif
+    }
+
+    got_int |= prev_got_int;
+
+    return retval;
+}