This document is a Mac OS X manual page. Manual pages are a command-line technology for providing documentation. You can view these manual pages locally using the man(1) command. These manual pages come from many different sources, and thus, have a variety of writing styles.

For more information about the manual page format, see the manual page for manpages(5).

UNGETC(3)                BSD Library Functions Manual                UNGETC(3)

NAME
     ungetc -- un-get character from input stream

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <stdio.h>

     int
     ungetc(int c, FILE *stream);

DESCRIPTION
     The ungetc() function pushes the character c (converted to an unsigned char) back onto the input stream
     pointed to by stream.  The pushed-back characters will be returned (in reverse order) by subsequent
     reads on the stream.  A successful intervening call to one of the file positioning functions (fseek(3),
     fsetpos(3), or rewind(3)), using the same stream, will discard the pushed-back characters.

     Only one character of push-back is guaranteed, but as long as there is sufficient memory, an effec-tively effectively
     tively infinite amount of push-back is allowed.

     If a character is successfully pushed-back, the end-of-file indicator for the stream is cleared.  The
     file-position indicator is decremented by each successful call to ungetc(); if its value was 0 before a
     call, its value is unspecified after the call.

RETURN VALUES
     The ungetc() function returns the character pushed-back after the conversion, or EOF if the operation
     fails.  If the value of the argument c character equals EOF, the operation will fail and the stream
     will remain unchanged.

SEE ALSO
     fseek(3), getc(3), setvbuf(3), ungetwc(3)

STANDARDS
     The ungetc() function conforms to ISO/IEC 9899:1990 (``ISO C90'').

BSD                              June 4, 1993                              BSD