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libio: Convert __vswprintf_internal to buffers (bug 27857)
Always null-terminate the buffer and set E2BIG if the buffer is too small. This fixes bug 27857. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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5365acc567
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@ -609,7 +609,6 @@ $(objpfx)tst-relro-libc.out: tst-relro-symbols.py $(..)/scripts/glibcelf.py \
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--required=_IO_wmem_jumps \
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--required=_IO_wprintf_buffer_as_file_jumps \
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--required=_IO_wstr_jumps \
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--required=_IO_wstrn_jumps \
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--optional=_IO_old_cookie_jumps \
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--optional=_IO_old_file_jumps \
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--optional=_IO_old_proc_jumps \
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@ -196,6 +196,7 @@ bool __printf_buffer_flush (struct __printf_buffer *buf) attribute_hidden;
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enum __wprintf_buffer_mode
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{
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__wprintf_buffer_mode_failed,
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__wprintf_buffer_mode_swprintf,
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__wprintf_buffer_mode_to_file,
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};
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@ -1,4 +1,5 @@
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#include <array_length.h>
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#include <errno.h>
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#include <stdio.h>
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#include <support/check.h>
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#include <sys/types.h>
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@ -37,6 +38,8 @@ do_test (void)
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for (n = 0; n < array_length (tests); ++n)
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{
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wmemset (buf, 0xabcd, array_length (buf));
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errno = 0;
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ssize_t res = swprintf (buf, tests[n].n, L"%s", tests[n].str);
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if (tests[n].exp < 0 && res >= 0)
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@ -52,9 +55,31 @@ do_test (void)
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swprintf (buf, %zu, L\"%%s\", \"%s\") expected to return %zd, but got %zd\n",
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tests[n].n, tests[n].str, tests[n].exp, res);
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}
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else
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printf ("swprintf (buf, %zu, L\"%%s\", \"%s\") OK\n",
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tests[n].n, tests[n].str);
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else if (res < 0
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&& tests[n].n > 0
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&& wcsnlen (buf, array_length (buf)) == array_length (buf))
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{
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support_record_failure ();
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printf ("\
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error: swprintf (buf, %zu, L\"%%s\", \"%s\") missing null terminator\n",
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tests[n].n, tests[n].str);
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}
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else if (res < 0
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&& tests[n].n > 0
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&& wcsnlen (buf, array_length (buf)) < array_length (buf)
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&& buf[wcsnlen (buf, array_length (buf)) + 1] != 0xabcd)
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{
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support_record_failure ();
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printf ("\
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error: swprintf (buf, %zu, L\"%%s\", \"%s\") out of bounds write\n",
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tests[n].n, tests[n].str);
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}
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if (res < 0 && tests[n].n < 0)
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TEST_COMPARE (errno, E2BIG);
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printf ("swprintf (buf, %zu, L\"%%s\", \"%s\") OK\n",
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tests[n].n, tests[n].str);
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}
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TEST_COMPARE (swprintf (buf, array_length (buf), L"%.0s", "foo"), 0);
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@ -24,101 +24,37 @@
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This exception applies to code released by its copyright holders
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in files containing the exception. */
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#include "libioP.h"
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#include "strfile.h"
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static wint_t _IO_wstrn_overflow (FILE *fp, wint_t c) __THROW;
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static wint_t
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_IO_wstrn_overflow (FILE *fp, wint_t c)
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{
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/* When we come to here this means the user supplied buffer is
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filled. But since we must return the number of characters which
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would have been written in total we must provide a buffer for
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further use. We can do this by writing on and on in the overflow
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buffer in the _IO_wstrnfile structure. */
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_IO_wstrnfile *snf = (_IO_wstrnfile *) fp;
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if (fp->_wide_data->_IO_buf_base != snf->overflow_buf)
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{
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_IO_wsetb (fp, snf->overflow_buf,
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snf->overflow_buf + (sizeof (snf->overflow_buf)
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/ sizeof (wchar_t)), 0);
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fp->_wide_data->_IO_write_base = snf->overflow_buf;
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fp->_wide_data->_IO_read_base = snf->overflow_buf;
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fp->_wide_data->_IO_read_ptr = snf->overflow_buf;
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fp->_wide_data->_IO_read_end = (snf->overflow_buf
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+ (sizeof (snf->overflow_buf)
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/ sizeof (wchar_t)));
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}
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fp->_wide_data->_IO_write_ptr = snf->overflow_buf;
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fp->_wide_data->_IO_write_end = snf->overflow_buf;
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/* Since we are not really interested in storing the characters
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which do not fit in the buffer we simply ignore it. */
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return c;
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}
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const struct _IO_jump_t _IO_wstrn_jumps libio_vtable attribute_hidden =
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{
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JUMP_INIT_DUMMY,
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JUMP_INIT(finish, _IO_wstr_finish),
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JUMP_INIT(overflow, (_IO_overflow_t) _IO_wstrn_overflow),
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JUMP_INIT(underflow, (_IO_underflow_t) _IO_wstr_underflow),
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JUMP_INIT(uflow, (_IO_underflow_t) _IO_wdefault_uflow),
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JUMP_INIT(pbackfail, (_IO_pbackfail_t) _IO_wstr_pbackfail),
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JUMP_INIT(xsputn, _IO_wdefault_xsputn),
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JUMP_INIT(xsgetn, _IO_wdefault_xsgetn),
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JUMP_INIT(seekoff, _IO_wstr_seekoff),
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JUMP_INIT(seekpos, _IO_default_seekpos),
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JUMP_INIT(setbuf, _IO_default_setbuf),
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JUMP_INIT(sync, _IO_default_sync),
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JUMP_INIT(doallocate, _IO_wdefault_doallocate),
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JUMP_INIT(read, _IO_default_read),
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JUMP_INIT(write, _IO_default_write),
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JUMP_INIT(seek, _IO_default_seek),
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JUMP_INIT(close, _IO_default_close),
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JUMP_INIT(stat, _IO_default_stat),
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JUMP_INIT(showmanyc, _IO_default_showmanyc),
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JUMP_INIT(imbue, _IO_default_imbue)
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};
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#include <errno.h>
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#include <math_ldbl_opt.h>
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#include <printf.h>
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#include <printf_buffer.h>
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int
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__vswprintf_internal (wchar_t *string, size_t maxlen, const wchar_t *format,
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va_list args, unsigned int mode_flags)
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{
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_IO_wstrnfile sf;
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int ret;
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struct _IO_wide_data wd;
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#ifdef _IO_MTSAFE_IO
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sf.f._sbf._f._lock = NULL;
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#endif
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if (maxlen == 0)
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/* Since we have to write at least the terminating L'\0' a buffer
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length of zero always makes the function fail. */
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return -1;
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_IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, 0, &wd, &_IO_wstrn_jumps);
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_IO_fwide (&sf.f._sbf._f, 1);
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string[0] = L'\0';
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_IO_wstr_init_static (&sf.f._sbf._f, string, maxlen - 1, string);
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ret = __vfwprintf_internal ((FILE *) &sf.f._sbf, format, args, mode_flags);
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struct __wprintf_buffer buf;
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__wprintf_buffer_init (&buf, string, maxlen, __wprintf_buffer_mode_swprintf);
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if (sf.f._sbf._f._wide_data->_IO_buf_base == sf.overflow_buf)
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/* ISO C99 requires swprintf/vswprintf to return an error if the
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output does not fit in the provided buffer. */
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return -1;
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__wprintf_buffer (&buf, format, args, mode_flags);
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/* Terminate the string. */
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*sf.f._sbf._f._wide_data->_IO_write_ptr = '\0';
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if (buf.write_ptr == buf.write_end)
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{
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/* Buffer has been filled exactly, excluding the null wide
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character. This is an error because the null wide character
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is required. */
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buf.write_end[-1] = L'\0';
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return -1;
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}
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return ret;
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buf.write_ptr[0] = L'\0';
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return __wprintf_buffer_done (&buf);
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}
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int
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@ -2412,9 +2412,10 @@ allocate at least @var{size} wide characters for the string @var{ws}.
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The return value is the number of characters generated for the given
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input, excluding the trailing null. If not all output fits into the
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provided buffer a negative value is returned. You should try again with
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a bigger output string. @emph{Note:} this is different from how
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@code{snprintf} handles this situation.
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provided buffer a negative value is returned, and @code{errno} is set to
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@code{E2BIG}. (The setting of @code{errno} is a GNU extension.) You
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should try again with a bigger output string. @emph{Note:} this is
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different from how @code{snprintf} handles this situation.
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Note that the corresponding narrow stream function takes fewer
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parameters. @code{swprintf} in fact corresponds to the @code{snprintf}
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@ -16,6 +16,7 @@
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <printf_buffer.h>
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#include "printf_buffer-wchar_t.h"
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@ -31,6 +32,11 @@ __wprintf_buffer_do_flush (struct __wprintf_buffer *buf)
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case __wprintf_buffer_mode_to_file:
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__wprintf_buffer_flush_to_file ((struct __wprintf_buffer_to_file *) buf);
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return;
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case __wprintf_buffer_mode_swprintf:
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buf->write_end[-1] = L'\0';
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__set_errno (E2BIG);
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__wprintf_buffer_mark_failed (buf);
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return;
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}
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__builtin_trap ();
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}
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