ungetwc(3) — Linux manual page

ungetwc(3)              Library Functions Manual              ungetwc(3)

NAME

       ungetwc - push back a wide character onto a FILE stream

LIBRARY

       Standard C library (libc, -lc)

SYNOPSIS

       #include <wchar.h>

       wint_t ungetwc(wint_t wc, FILE *stream);

DESCRIPTION

       The ungetwc() function is the wide-character equivalent of the
       ungetc(3) 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 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

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

ATTRIBUTES

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

STANDARDS

       C11, POSIX.1-2008.

HISTORY

       POSIX.1-2001, C99.

NOTES

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

SEE ALSO

       fgetwc(3)

COLOPHON

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Linux man-pages 6.9.1          2024-05-02                     ungetwc(3)

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

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