ungetwc(3) - Linux manual page (original) (raw)

ungetwc(3) Library Functions Manual ungetwc(3)

NAME top

   ungetwc - push back a wide character onto a FILE stream

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <wchar.h>**

   **wint_t ungetwc(wint_t** _wc_**, FILE ***_stream_**);**

DESCRIPTION top

   The **ungetwc**() function is the wide-character equivalent of the
   [ungetc(3)](../man3/ungetc.3.html) function.  It pushes back a wide character onto _stream_
   and returns it.

   If _wc_ is **WEOF**, it returns **WEOF**.  If _wc_ is an invalid wide
   character, it sets _[errno](../man3/errno.3.html)_ to **EILSEQ** and returns **WEOF**.

   If _wc_ is a valid wide character, it is pushed back onto the stream
   and thus becomes available for future wide-character read
   operations.  The file-position indicator is decremented by one or
   more.  The end-of-file indicator is cleared.  The backing storage
   of the file is not affected.

   Note: _wc_ need not be the last wide-character read from the stream;
   it can be any other valid wide character.

   If the implementation supports multiple push-back operations in a
   row, the pushed-back wide characters will be read in reverse
   order; however, only one level of push-back is guaranteed.

RETURN VALUE top

   The **ungetwc**() function returns _wc_ when successful, or **WEOF** upon
   failure.

ATTRIBUTES top

   For an explanation of the terms used in this section, see
   [attributes(7)](../man7/attributes.7.html).
   ┌──────────────────────────────────────┬───────────────┬─────────┐
   │ **Interface** │ **Attribute** │ **Value** │
   ├──────────────────────────────────────┼───────────────┼─────────┤
   │ **ungetwc**()                            │ Thread safety │ MT-Safe │
   └──────────────────────────────────────┴───────────────┴─────────┘

STANDARDS top

   C11, POSIX.1-2008.

HISTORY top

   POSIX.1-2001, C99.

NOTES top

   The behavior of **ungetwc**() depends on the **LC_CTYPE** category of the
   current locale.

SEE ALSO top

   [fgetwc(3)](../man3/fgetwc.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-07-23 ungetwc(3)

Pages that refer to this page:fgetc(3), fgetwc(3), gets(3)