ungetwc − push back a wide character onto a FILE stream #include<wchar.h> , FILE *wint_t ungetwc(wint_t wc The function is the wide‐character equivalent of the function. It pushes back a wide character onto stream and returns it. If wc is it returns If wc is an invalid wide character, it sets errno to EILSEQ and returns 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. The function returns wc when successful, or WEOF upon failure. For an explanation of the terms used in this section, see ┌──────────┬───────────────┬─────────┐ │Interface │ Attribute │ Value │ ├──────────┼───────────────┼─────────┤ │ │ Thread safety │ MT‐Safe │ └──────────┴───────────────┴─────────┘ POSIX.1‐2001, POSIX.1‐2008, C99. The behavior of depends on the LC_CTYPE category of the current locale. This page is part of release 5.07 of the Linux man‐pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man−pages/.