O nás     Inzerce     KontaktSpolehlivé informace o IT již od roku 2011
Hledat
Nepřehlédněte: 2. kolo: Pozoruhodné IT produkty 2020
Správa dokumentů
Digitální transformace
Informační systémy
Hlavní rubriky: Informační systémy, Mobilní technologie, Datová centra, Sítě, IT bezpečnost, Software, Hardware, Zkušenosti a názory, Speciály

Pozoruhodné IT produkty 2020
E-knihy o IT zdarma
Odborné IT konference BusinessIT
Manuál Linux
[Linux manuál]

ungetwc: posuňte široký znakový kód zpět do vstupního proudu

Originální popis anglicky: ungetwc - push wide-character code back into the input stream

Návod, kniha: POSIX Programmer's Manual

STRUČNĚ

#include <stdio.h>
 
#include <wchar.h>
 
 
wint_t ungetwc(wint_t wc, FILE *stream );
 

POPIS / INSTRUKCE

The ungetwc() function shall push the character corresponding to the wide-character code specified by wc back onto the input stream pointed to by stream. The pushed-back characters shall be returned by subsequent reads on that stream in the reverse order of their pushing. A successful intervening call (with the stream pointed to by stream) to a file-positioning function ( fseek(), fsetpos(), or rewind()) discards any pushed-back characters for the stream. The external storage corresponding to the stream is unchanged.
At least one character of push-back shall be provided. If ungetwc() is called too many times on the same stream without an intervening read or file-positioning operation on that stream, the operation may fail.
If the value of wc equals that of the macro WEOF, the operation shall fail and the input stream shall be left unchanged.
A successful call to ungetwc() shall clear the end-of-file indicator for the stream. The value of the file-position indicator for the stream after reading or discarding all pushed-back characters shall be the same as it was before the characters were pushed back. The file-position indicator is decremented (by one or more) by each successful call to ungetwc(); if its value was 0 before a call, its value is unspecified after the call.

NÁVRATOVÁ HODNOTA

Upon successful completion, ungetwc() shall return the wide-character code corresponding to the pushed-back character. Otherwise, it shall return WEOF.

CHYBY / ERRORY

The ungetwc() function may fail if:
EILSEQ
An invalid character sequence is detected, or a wide-character code does not correspond to a valid character.
 
The following sections are informative.

PŘÍKLADY POUŽITÍ

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SOUVISEJÍCÍ

fseek() , fsetpos() , read() , rewind() , setbuf() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>, <wchar.h> Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .
2003 IEEE/The Open Group
©2011-2020 BusinessIT.cz, ISSN 1805-0522 | Názvy použité v textech mohou být ochrannými známkami příslušných vlastníků.
Provozovatel: Bispiral, s.r.o., kontakt: BusinessIT(at)Bispiral.com | Inzerce: Best Online Media, s.r.o., zuzana@online-media.cz
O vydavateli | Pravidla webu BusinessIT.cz a ochrana soukromí | pg(8529)