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-rw-r--r--libio/vswprintf.c26
1 files changed, 12 insertions, 14 deletions
diff --git a/libio/vswprintf.c b/libio/vswprintf.c
index 25274926f6..00dc62c902 100644
--- a/libio/vswprintf.c
+++ b/libio/vswprintf.c
@@ -1,4 +1,4 @@
-/* Copyright (C) 1994, 1997, 1999, 2000 Free Software Foundation, Inc.
+/* Copyright (C) 1994, 1997, 1999, 2000, 2001 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -54,11 +54,6 @@ _IO_wstrn_overflow (fp, c)
if (fp->_wide_data->_IO_buf_base != snf->overflow_buf)
{
- /* Terminate the string. We know that there is room for at
- least one more character since we initialized the stream with
- a size to make this possible. */
- *fp->_wide_data->_IO_write_ptr = '\0';
-
_IO_wsetb (fp, snf->overflow_buf,
snf->overflow_buf + (sizeof (snf->overflow_buf)
/ sizeof (wchar_t)), 0);
@@ -120,13 +115,10 @@ _IO_vswprintf (string, maxlen, format, args)
sf.f._sbf._f._lock = &lock;
#endif
- /* We need to handle the special case where MAXLEN is 0. Use the
- overflow buffer right from the start. */
if (maxlen == 0)
- {
- string = sf.overflow_buf;
- maxlen = sizeof (sf.overflow_buf) / sizeof (wchar_t);
- }
+ /* Since we have to write at least the terminating L'\0' a buffer
+ length of zero always makes the function fail. */
+ return -1;
_IO_no_init (&sf.f._sbf._f, 0, 0, &wd, &_IO_wstrn_jumps);
_IO_fwide (&sf.f._sbf._f, 1);
@@ -134,8 +126,14 @@ _IO_vswprintf (string, maxlen, format, args)
_IO_wstr_init_static (&sf.f._sbf._f, string, maxlen - 1, string);
ret = _IO_vfwprintf ((_IO_FILE *) &sf.f._sbf, format, args);
- if (sf.f._sbf._f._wide_data->_IO_buf_base != sf.overflow_buf)
- *sf.f._sbf._f._wide_data->_IO_write_ptr = '\0';
+ if (sf.f._sbf._f._wide_data->_IO_buf_base == sf.overflow_buf)
+ /* ISO C99 requires swprintf/vswprintf to return an error if the
+ output does not fit int he provided buffer. */
+ return -1;
+
+ /* Terminate the string. */
+ *sf.f._sbf._f._wide_data->_IO_write_ptr = '\0';
+
return ret;
}